Transmission apparatus and transmission method

ABSTRACT

A transmission apparatus includes M signal processors that respectively generate modulated signals directed to M reception apparatuses, M being an integer equal to or greater than 2, and an antenna section. Each signal processor modulates a first bit sequence made up of two bits to generate a first modulated signal and a second modulated signal, and modulates a second bit sequence made up of other two bits to generate a third modulated signal and a fourth modulated signal, in a case of transmitting multiple streams to a corresponding one of the M reception apparatuses. The antenna section includes a first antenna that transmits the first modulated signal and the third modulated signal and a second antenna that transmits the second modulated signal and the fourth modulated signal. At least either the signals transmitted from the first antenna or the signals transmitted from the second antenna are phase-changed signals.

BACKGROUND 1. Technical Field

The present disclosure relates to a transmission apparatus and atransmission method.

2. Description of the Related Art

A communication method called Multiple-Input Multiple-Output (MIMO), forexample, is known as a communication method using multiple antennas. Inmulti-antenna communication for a single user represented by MIMO,multiple sequences of transmission data are individually modulated,modulated signals obtained accordingly are simultaneously transmittedfrom different antennas, and thus the data communication speed isincreased.

FIG. 33 is a diagram illustrating an example of the configuration of atransmission apparatus that is based on the Digital VideoBroadcasting-Next Generation Handheld (DVB-NGH) standard in a case wherethe number of transmission antennas is two and the number of modulatedtransmission signals (transmission streams) is two, which is describedin “MIMO for DVB-NGH, the next generation mobile TV broadcasting,” IEEECommun. Mag., vol. 57, no. 7, pp. 130-137, July 2013. In thetransmission apparatus, data 1 is input and coded by an encoder 2 toobtain data 3, which is divided into data 5A and data 5B by adistributer 4. The data 5A is subjected to interleaving processingperformed by an interleaver 4A and mapping processing performed by amapper 6A. Likewise, the data 5B is subjected to interleaving processingperformed by an interleaver 4B and mapping process performed by a mapper6B. The coding processing in the encoder 2, the interleaving processingin the interleavers 4A and 4B, and the mapping processing in the mappers6A and 6B are performed on the basis of setting information included ina frame configuration signal 13.

Weight combiners 8A and 8B receive mapped signals 7A and 7B and performweight combining thereon to generate weight combined signals 9A and 16B,respectively. After that, the weight combined signal 16B is subjected tophase change performed by a phase changer 17B, and a phase-changedsignal 9B is output. Subsequently, radio sections 10A and 10B perform,for example, processing related to orthogonal frequency divisionmultiplexing (OFDM), such as frequency conversion and amplification. Inaddition, a transmission signal 11A is transmitted from an antenna 12A,and a transmission signal 11B is transmitted from an antenna 12B. Theweight combining processing in the weight combiners 8A and 8B and thephase change processing in the phase changer 17B are performed on thebasis of signal processing method information 115 generated by a signalprocessing method information generator 114. The signal processingmethod information generator 114 generates the signal processing methodinformation 115 on the basis of the frame configuration signal 13. Atthis time, in the phase changer 17B, for example, nine phase changevalues are provided and phase change in a period of 9 is regularlyperformed.

Accordingly, there is a high possibility of being able to avoid asituation where a reception apparatus as a communication partner fallsinto a steadily poor reception state in an environment in which directwaves are dominant. Accordingly, it is possible to improve the datareception quality at the reception apparatus as a communication partner.

SUMMARY

However, the transmission apparatus in FIG. 33 does not considertransmitting modulated signals to multiple terminals (multiple users)using identical times and identical frequencies (identical frequencybands).

One non-limiting and exemplary embodiment provides a transmissionapparatus capable of transmitting modulated signals to multipleterminals (multiple users) by using identical times and identicalfrequencies (identical frequency bands). In particular, whentransmitting modulated signals of multiple streams to the individualterminals (individual users), it is possible to avoid a situation wherea reception apparatus as a communication partner falls into a steadilypoor reception state in an environment in which direct waves aredominant. Accordingly, the data reception quality at the receptionapparatus as a communication partner is improved.

In one general aspect, the techniques disclosed here feature atransmission apparatus including M signal processors that respectivelygenerate modulated signals directed to M reception apparatuses, M beingan integer equal to or greater than 2. Each of the M signal processorsmodulates a first bit sequence made up of two bits to generate a firstmodulated signal and a second modulated signal, and modulates a secondbit sequence made up of other two bits to generate a third modulatedsignal and a fourth modulated signal, in a case of transmitting multiplestreams to a corresponding one of the M reception apparatuses. Thetransmission apparatus also includes an antenna section including afirst antenna that transmits the first modulated signal and the thirdmodulated signal and a second antenna that transmits the secondmodulated signal and the fourth modulated signal, at least either thesignals transmitted from the first antenna or the signals transmittedfrom the second antenna being phase-changed signals.

It should be noted that general or specific embodiments may beimplemented as a system, a method, an integrated circuit, a computerprogram, a recording medium, or any selective combination thereof.

According to an aspect of the present disclosure, when transmittingmodulated signals of multiple streams to individual terminals(individual users), it is possible to avoid a situation where eachterminal falls into a steadily poor reception state in an environment inwhich direct waves are dominant. Accordingly, it is possible to improvethe data reception quality in a reception apparatus as a communicationpartner.

Additional benefits and advantages of the disclosed embodiments willbecome apparent from the specification and drawings. The benefits and/oradvantages may be individually obtained by the various embodiments andfeatures of the specification and drawings, which need not all beprovided in order to obtain one or more of such benefits and/oradvantages.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating an example of the configuration of atransmission apparatus according to an embodiment of the presentdisclosure;

FIG. 2 is a diagram illustrating an example of the configuration of asignal processor for a user #p;

FIG. 3 is a diagram illustrating an example of the configuration of thesignal processor in FIG. 2 ;

FIG. 4 is a diagram illustrating an example of the configuration of thesignal processor in FIG. 2 different from FIG. 3 ;

FIG. 5 is a diagram illustrating an example of the configuration of aradio section $n that uses the OFDM scheme;

FIG. 6 is a diagram illustrating an example of the configuration of anantenna section in FIG. 1 ;

FIG. 7 is a diagram illustrating an example of the configuration of aportion related to control information generation for generating acontrol information symbol signal in FIGS. 3 and 4 ;

FIG. 8 is a diagram illustrating an example of the frame configurationof a first baseband signal for the user #p;

FIG. 9 is a diagram illustrating an example of the frame configurationof a second baseband signal for the user #p;

FIG. 10 is a diagram illustrating another example of the frameconfiguration of the first baseband signal for the user #p;

FIG. 11 is a diagram illustrating another example of the frameconfiguration of the second baseband signal for the user #p;

FIG. 12 is a diagram illustrating an example of a method for arrangingsymbols with respect to a time axis;

FIG. 13 is a diagram illustrating an example of a method for arrangingsymbols with respect to a frequency axis;

FIG. 14 is a diagram illustrating an example of arrangement of symbolswith respect to the time and frequency axes;

FIG. 15 is a diagram illustrating an example of arrangement of symbolswith respect to the time axis;

FIG. 16 is a diagram illustrating an example of arrangement of symbolswith respect to the frequency axis;

FIG. 17 is a diagram illustrating an example of arrangement of symbolswith respect to the time and frequency axes;

FIG. 18 is a diagram illustrating the configuration of a multiplexingsignal processor that includes an interleaver;

FIG. 19 is a diagram illustrating an example of the configuration of areception apparatus according to the present embodiment;

FIG. 20 is a diagram illustrating the relationship between thetransmission apparatus and the reception apparatus;

FIG. 21 is a diagram illustrating an example of the configuration of theantenna section in FIG. 19 ;

FIG. 22 is a diagram illustrating an example of the configuration of abase station (AP) including the transmission apparatus in FIG. 1 ;

FIG. 23 is a diagram illustrating an example of the configuration of aterminal including the reception apparatus in FIG. 19 ;

FIG. 24 is a diagram illustrating an example of the relationship betweenthe base station (AP) and terminals;

FIG. 25 is a diagram illustrating an example of a temporal flow ofcommunication between the base station (AP) and the terminals;

FIG. 26 is a diagram illustrating an example of the configuration of thesignal processor in FIG. 2 different from FIG. 3 ;

FIG. 27 is a diagram illustrating an example of communication betweenthe base station (AP) and a terminal #p;

FIG. 28 is a diagram illustrating an example of data included in areception capability notification symbol;

FIG. 29 is a diagram illustrating an example of data included in thereception capability notification symbol different from FIG. 28 ;

FIG. 30 is a diagram illustrating an example of data included in thereception capability notification symbol different from FIGS. 28 and 29;

FIG. 31 is a diagram illustrating an example of the configuration of thesignal processor for the user #p;

FIG. 32 is a diagram illustrating an example of the configuration of thesignal processor for the user #p;

FIG. 33 is a diagram illustrating an example of the configuration of atransmission apparatus that is based on the DVB-NGH standard describedin “MIMO for DVB-NGH, the next generation mobile TV broadcasting,” IEEECommun. Mag., vol. 57, no. 7, pp. 130-137, July 2013;

FIG. 34 is a diagram illustrating an example of the configuration of theterminal #p as a communication partner of the base station illustratedin FIG. 24 ;

FIG. 35 is a diagram illustrating an example of the configuration of thereception apparatus of the terminal #p illustrated in FIG. 34 ;

FIG. 36 is a diagram illustrating an example of the frame configurationof a modulated signal of a single stream transmitted by using amulti-carrier transmission scheme such as the OFDM scheme;

FIG. 37 is a diagram illustrating an example of the frame configurationof a modulated signal of a single stream transmitted by using asingle-carrier transmission scheme;

FIG. 38 is a diagram illustrating still another example of theconfiguration of the signal processor in FIG. 2 ;

FIG. 39 is a diagram illustrating still another example of theconfiguration of the signal processor in FIG. 2 ;

FIG. 40 is a diagram illustrating a first example in which phasechangers are arranged upstream and downstream of a weight combiner;

FIG. 41 is a diagram illustrating a second example in which phasechangers are arranged upstream and downstream of the weight combiner;

FIG. 42 is a diagram illustrating a third example in which phasechangers are arranged upstream and downstream of the weight combiner;

FIG. 43 is a diagram illustrating a fourth example in which phasechangers are arranged upstream and downstream of the weight combiner;

FIG. 44 is a diagram illustrating a fifth example in which phasechangers are arranged upstream and downstream of the weight combiner;

FIG. 45 is a diagram illustrating a sixth example in which phasechangers are arranged upstream and downstream of the weight combiner;

FIG. 46 is a diagram illustrating a seventh example in which phasechangers are arranged upstream and downstream of the weight combiner;

FIG. 47 is a diagram illustrating an eighth example in which phasechangers are arranged upstream and downstream of the weight combiner;

FIG. 48 is a diagram illustrating a ninth example in which phasechangers are arranged upstream and downstream of the weight combiner;

FIG. 49 is a diagram illustrating a first example configuration on theoutput side of an inserter;

FIG. 50 is a diagram illustrating a second example configuration on theoutput side of the inserter;

FIG. 51 is a diagram illustrating a third example configuration on theoutput side of the inserter;

FIG. 52 is a diagram illustrating a fourth example configuration on theoutput side of the inserter;

FIG. 53 is a diagram illustrating a fifth example configuration on theoutput side of the inserter;

FIG. 54 is a diagram illustrating a sixth example configuration on theoutput side of the inserter;

FIG. 55 is a diagram for describing CDD (CSD);

FIG. 56 is a diagram illustrating an example of the configuration of thesignal processor for the user #p different from FIG. 2 ;

FIG. 57 is a diagram illustrating a first example of the operation of amapper;

FIG. 58 is a diagram illustrating a first example of signal pointarrangement of QPSK modulation on the in-phase I quadrature Q plane;

FIG. 59 is a diagram illustrating a second example of signal pointarrangement of QPSK modulation on the in-phase I quadrature Q plane;

FIG. 60 is a diagram illustrating a third example of signal pointarrangement of QPSK modulation on the in-phase I quadrature Q plane;

FIG. 61 is a diagram illustrating a fourth example of signal pointarrangement of QPSK modulation on the in-phase I quadrature Q plane;

FIG. 62 is a diagram illustrating an example of the configuration of thesignal processor for the user #p different from FIGS. 2 and 56 ;

FIG. 63 is a diagram illustrating a second example of the operation ofthe mapper;

FIG. 64 is a diagram illustrating a third example of the operation ofthe mapper;

FIG. 65 is a diagram illustrating a fourth example of the operation ofthe mapper;

FIG. 66 is a diagram illustrating a fifth example of the operation ofthe mapper;

FIG. 67 is a diagram illustrating a sixth example of the operation ofthe mapper;

FIG. 68A is a diagram illustrating a first example of the state ofsignal points of signals transmitted by the transmission apparatusincluding the configuration in FIG. 3 ;

FIG. 68B is a diagram illustrating a first example of the state ofsignal points of signals received by the reception apparatus as acommunication partner of the transmission apparatus including theconfiguration in FIG. 3 ;

FIG. 69A is a diagram illustrating a second example of the state ofsignal points of signals transmitted by the transmission apparatusincluding the configuration in FIG. 3 ;

FIG. 69B is a diagram illustrating a second example of the state ofsignal points of signals received by the reception apparatus as acommunication partner of the transmission apparatus including theconfiguration in FIG. 3 ;

FIG. 70 is a diagram illustrating an example configuration of thetransmission apparatus of the base station (AP) different from FIG. 1 ;

FIG. 71 is a diagram illustrating an example of data included in thereception capability notification symbol different from FIGS. 28, 29,and 30 ;

FIG. 72 is a diagram illustrating an example of the configuration of aframe;

FIG. 73 is a diagram illustrating an example of carrier groups ofmodulated signals transmitted by the base station or AP;

FIG. 74 is a diagram illustrating an example of carrier groups ofmodulated signals transmitted by the base station or AP different fromFIG. 73 ;

FIG. 75 is a diagram illustrating an example of a configuration addedwith a phase changer;

FIG. 76 is a diagram illustrating a first example configuration of thesignal processor for the user #p in FIGS. 1 and 70 ;

FIG. 77 is a diagram illustrating a second example configuration of thesignal processor for the user #p in FIGS. 1 and 70 ;

FIG. 78 is a diagram illustrating a first example of the configurationincluded in control information symbols or the like;

FIG. 79 is a diagram illustrating a second example of the configurationincluded in control information symbols or the like;

FIG. 80 is a diagram illustrating a specific example configuration ofthe reception capability notification symbol transmitted by the terminal#p illustrated in FIG. 27 ;

FIG. 81 is a diagram illustrating an example of the configuration of“single-carrier scheme and OFDM scheme related reception capabilitynotification symbol” illustrated in FIG. 80 ;

FIG. 82 is a diagram illustrating an example of the configuration of“single-carrier scheme related reception capability notification symbol”illustrated in FIG. 80 ;

FIG. 83 is a diagram illustrating an example of the configuration of“OFDM scheme related reception capability notification symbol”illustrated in FIG. 80 ;

FIG. 84 is a diagram illustrating another example of a specificconfiguration of the reception capability notification symboltransmitted by the terminal #p illustrated in FIG. 27 ;

FIG. 85 is a diagram illustrating an example of the configuration of“OFDM scheme related reception capability notification symbol”illustrated in FIG. 80 ;

FIG. 86 is a diagram illustrating an example of the configuration of“OFDM scheme related reception capability notification symbol”illustrated in FIG. 80 ;

FIG. 87 is a diagram illustrating an example of the configuration of“OFDM scheme related reception capability notification symbol”illustrated in FIG. 80 ;

FIG. 88 is a diagram illustrating an example of the configuration of“OFDM scheme related reception capability notification symbol”illustrated in FIG. 80 ;

FIG. 89 is a diagram illustrating an example of the format of thereception capability notification symbol;

FIG. 90 is a diagram illustrating an example of the format of anExtended Capabilities field;

FIG. 91 is a diagram illustrating a first example of the ExtendedCapabilities field;

FIG. 92 is a diagram illustrating a second example of the ExtendedCapabilities field;

FIG. 93 is a diagram illustrating a third example of the ExtendedCapabilities field;

FIG. 94 is a diagram illustrating a fourth example of the ExtendedCapabilities field;

FIG. 95 is a diagram illustrating a fifth example of the ExtendedCapabilities field;

FIG. 96 is a diagram illustrating an example of data included in thereception capability notification symbol;

FIG. 97 is a diagram illustrating another example of data included inthe reception capability notification symbol;

FIG. 98 is a diagram illustrating still another example of data includedin the reception capability notification symbol;

FIG. 99 is a diagram illustrating still another example of data includedin the reception capability notification symbol;

FIG. 100 is a diagram illustrating still another example of dataincluded in the reception capability notification symbol;

FIG. 101 is a diagram illustrating still another example of dataincluded in the reception capability notification symbol;

FIG. 102 is a diagram illustrating an example of the configuration of afirst signal processor;

FIG. 103 is a diagram illustrating an example of the configuration of asecond signal processor;

FIG. 104 is a diagram illustrating an example of the relationshipbetween the base station (AP) and the terminal; and

FIG. 105 is a diagram illustrating an example configuration of thetransmission apparatus of the base station (AP) different from FIG. 1 .

DETAILED DESCRIPTION

Hereinafter, embodiments of the present disclosure will be described indetail with reference to the drawings. The individual embodimentsdescribed below are examples, and the present disclosure is not limitedto these embodiments.

First Embodiment

A detailed description will be given of a transmission method, atransmission apparatus, a reception method, and a reception apparatusaccording to the present embodiment.

Example of Configuration of Transmission Apparatus in Present Embodiment

FIG. 1 is a diagram illustrating an example of the configuration of thetransmission apparatus in the present embodiment. The transmissionapparatus illustrated in FIG. 1 is, for example, a base station, anaccess point, a broadcast station, or the like. The transmissionapparatus is a transmission apparatus that generates modulated signalsto be transmitted to a user #1 reception apparatus (terminal) to a user#M reception apparatus (terminal) (M is an integer equal to or greaterthan 2) and transmits the modulated signals.

The transmission apparatus illustrated in FIG. 1 includes a user #1signal processor 102_1 to a user #M signal processor 102_M, amultiplexing signal processor 104, a radio section $1 (106_1) to a radiosection $N (106_N), and an antenna section $1 (108_1) to an antennasection $N (108_N) (N is an integer equal to or greater than 1).

The user #1 signal processor 102_1 receives a control signal 100 anduser #1 data 101_1. On the basis of information about a transmissionmethod for generating a user #1 modulated signal included in the controlsignal 100, the user #1 signal processor 102_1 performs signalprocessing and generates a user #1 first baseband signal 103_1_1 and/ora user #1 second baseband signal 103_1_2. The user #1 signal processor102_1 outputs the generated user #1 first baseband signal 103_1_1 and/oruser #1 second baseband signal 103_1_2 to the multiplexing signalprocessor 104. The transmission method for generating a modulated signalincludes, for example, an error-correcting coding method (the codingrate of an error-correcting code and the code length of theerror-correcting code), a modulation scheme, a transmission method (forexample, single-stream transmission and multi-stream transmission), andthe like.

For example, in a case where the control signal 100 includes informationindicating that multi-stream transmission is selected, the user #1signal processor 102_1 generates the user #1 first baseband signal103_1_1 and the user #1 second baseband signal 103_1_2. In a case wherethe control signal 100 includes information indicating thatsingle-stream transmission is selected, the user #1 signal processor102_1 generates the user #1 first baseband signal 103_1_1.

Likewise, the user #2 signal processor 102_2 receives the control signal100 and user #2 data 101_2. On the basis of information about atransmission method for generating a user #2 modulated signal includedin the control signal 100, the user #2 signal processor 102_2 performssignal processing and generates a user #2 first baseband signal 103_2_1and/or a user #2 second baseband signal 103_2_2. The user #2 signalprocessor 102_2 outputs the generated user #2 first baseband signal103_2_1 and/or user #2 second baseband signal 103_2_2 to themultiplexing signal processor 104. The transmission method forgenerating a modulated signal includes, for example, an error-correctingcoding method (the coding rate of an error-correcting code and the codelength of the error-correcting code), a modulation scheme, atransmission method (for example, single-stream transmission andmulti-stream transmission), and the like.

For example, in a case where the control signal 100 includes informationindicating that multi-stream transmission is selected, the user #2signal processor 102_2 generates the user #2 first baseband signal103_2_1 and the user #2 second baseband signal 103_2_2. In a case wherethe control signal 100 includes information indicating thatsingle-stream transmission is selected, the user #2 signal processor102_2 generates the user #2 first baseband signal 103_2_1.

Likewise, the user #M signal processor 102_M receives the control signal100 and user #M data 101_M. On the basis of information about atransmission method for generating a user #M modulated signal includedin the control signal 100, the user #M signal processor 102_M performssignal processing and generates a user #M first baseband signal 103_M_1and/or a user #M second baseband signal 103_M_2. The user #M signalprocessor 102_M outputs the generated user #M first baseband signal103_M_1 and/or user #M second baseband signal 103_M_2 to themultiplexing signal processor 104. The transmission method forgenerating a modulated signal includes, for example, an error-correctingcoding method (the coding rate of an error-correcting code and the codelength of the error-correcting code), a modulation scheme, atransmission method (for example, single-stream transmission andmulti-stream transmission), and the like.

For example, in a case where the control signal 100 includes informationindicating that multi-stream transmission is selected, the user #Msignal processor 102_M generates the user #M first baseband signal103_M_1 and the user #M second baseband signal 103_M_2. In a case wherethe control signal 100 includes information indicating thatsingle-stream transmission is selected, the user #M signal processor102_M generates the user #M first baseband signal 103_M_1.

Accordingly, a user #p signal processor 102_p (p is an integer from 1 toM) receives the control signal 100 and user #p data 101_p. On the basisof information about a transmission method for generating a user #pmodulated signal (for example, an error-correcting coding method (thecoding rate of an error-correcting code and the code length of theerror-correcting code), a modulation scheme, a transmission method (forexample, single-stream transmission and multi-stream transmission), andthe like) included in the control signal 100, the user #p signalprocessor 102_p performs signal processing and generates a user #p firstbaseband signal 103_p_1 and/or a user #p second baseband signal 103_p_2.The user #p signal processor 102_p outputs the generated user #p firstbaseband signal 103_p_1 and/or user #p second baseband signal 103_p_2 tothe multiplexing signal processor 104.

For example, in a case where the control signal 100 includes informationindicating that multi-stream transmission is selected, the user #psignal processor 102_p generates the user #p first baseband signal103_p_1 and the user #p second baseband signal 103_p_2. In a case wherethe control signal 100 includes information indicating thatsingle-stream transmission is selected, the user #p signal processor102_p generates the user #p first baseband signal 103_p_1.

The configuration of each of the user #1 signal processor 102_1 to theuser #M signal processor 102_M will be described below by taking theconfiguration of the user #p signal processor as an example.

The control signal 100 includes information indicating which ofmulti-stream transmission and single-stream transmission is selected foreach of the user #1 signal processor 102_1 to the user #M signalprocessor 102_M.

The multiplexing signal processor 104 receives the control signal 100,the user #1 first baseband signal 103_1_1, the user #1 second basebandsignal 103_1_2, the user #2 first baseband signal 103_2_1, the user #2second baseband signal 103_2_2, . . . , the user #M first basebandsignal 103_M_1, the user #M second baseband signal 103_M_2, and a(common) reference signal 199. On the basis of the control signal 100,the multiplexing signal processor 104 performs multiplexing signalprocessing and generates a multiplexed signal $1 baseband signal 105_1to a multiplexed signal $N baseband signal 105_N (N is an integer equalto or greater than 1). The multiplexing signal processor 104 outputs thegenerated multiplexed signal $1 baseband signal 105_1 to multiplexedsignal $N baseband signal 105_N to the corresponding radio sections (theradio section $1 to the radio section $N).

The (common) reference signal 199 is a signal that is transmitted fromthe transmission apparatus for the reception apparatus to estimate apropagation environment. The (common) reference signal 199 is insertedinto the baseband signal of each user. The multiplexing signalprocessing will be described below.

The radio section $1 (106_1) receives the control signal 100 and themultiplexed signal $1 baseband signal 105_1. On the basis of the controlsignal 100, the radio section $1 (106_1) performs processing such asfrequency conversion and amplification, and outputs a transmissionsignal 107_1 to the antenna section $1 (108_1).

The antenna section $1 (108_1) receives the control signal 100 and thetransmission signal 107_1. On the basis of the control signal 100, theantenna section $1 (108_1) performs processing on the transmissionsignal 107_1. Note that, in the antenna section $1 (108_1), the controlsignal 100 need not necessarily exist as input. The transmission signal107_1 is output as a radio wave from the antenna section $1 (108_1).

The radio section $2 (106_2) receives the control signal 100 and themultiplexed signal $2 baseband signal 105_2. On the basis of the controlsignal 100, the radio section $2 (106_2) performs processing such asfrequency conversion and amplification, and outputs a transmissionsignal 107_2 to the antenna section $2 (108_2).

The antenna section $2 (108_2) receives the control signal 100 and thetransmission signal 107_2. On the basis of the control signal 100, theantenna section $2 (108_2) performs processing on the transmissionsignal 107_2. Note that, in the antenna section $2 (108_2), the controlsignal 100 need not necessarily exist as input. The transmission signal107_2 is output as a radio wave from the antenna section $2 (108_2).

The radio section $N (106_N) receives the control signal 100 and themultiplexed signal $N baseband signal 105_N. On the basis of the controlsignal 100, the radio section $N (106_N) performs processing such asfrequency conversion and amplification, and outputs a transmissionsignal 107_N to the antenna section $N (108_N).

The antenna section $N (108_N) receives the control signal 100 and thetransmission signal 107_N. On the basis of the control signal 100, theantenna section $N (108_N) performs processing on the transmissionsignal 107_N. Note that, in the antenna section $N (108_N), the controlsignal 100 need not necessarily exist as input. The transmission signal107_N is output as a radio wave from the antenna section $N (108_N).

Accordingly, a radio section $n (106_n) (n is an integer from 1 to N)receives the control signal 100 and a multiplexed signal $n basebandsignal 105_n. On the basis of the control signal 100, the radio section$n (106_n) performs processing such as frequency conversion andamplification, and outputs a transmission signal 107_n to an antennasection $n (108_n).

The antenna section $n (108_n) receives the control signal 100 and thetransmission signal 107_n. On the basis of the control signal 100, theantenna section $n (108_n) performs processing on the transmissionsignal 107_n. Note that, in the antenna section $n (108_n), the controlsignal 100 need not necessarily exist as input. The transmission signal107_n is output as a radio wave from the antenna section $n (108_n).

An example of the configurations of the radio sections $1 to $N and theantenna sections $1 to $N will be described below.

The control signal 100 may be generated on the basis of informationtransmitted to the transmission apparatus in FIG. 1 by the receptionapparatus as a communication partner of FIG. 1 . Alternatively, thetransmission apparatus in FIG. 1 may include an input section, and thecontrol signal 100 may be generated on the basis of information inputfrom the input section.

In the transmission apparatus in FIG. 1 , not all the user #1 signalprocessor (102_1) to the user #M signal processor (102_M) may beoperating. All of them may be operating or some of them may beoperating. That is, the number of users with which the transmissionapparatus is communicating is 1 to M. The number of communicationpartners (users) to which the transmission apparatus in FIG. 1 transmitsa modulated signal is 1 to M.

Also, not all the radio section $1 (106_1) to the radio section $N(106_N) may be operating. All of them may be operating or some of themmay be operating. Also, not all the antenna section $1 (108_1) to theantenna section $N (108_N) may be operating. All of them may beoperating or some of them may be operating.

As described above, the transmission apparatus in FIG. 1 is able totransmit modulated signals (baseband signals) for multiple users byusing identical times and identical frequencies (bands) and by usingmultiple antennas.

For example, the transmission apparatus in FIG. 1 is able to transmitthe user #1 first baseband signal 103_1_1, the user #1 second basebandsignal 103_1_2, the user #2 first baseband signal 103_2_1, and the user#2 second baseband signal 103_2_2 by using identical times and identicalfrequencies (bands). Also, the transmission apparatus in FIG. 1 is ableto transmit the user #1 first baseband signal 103_1_1, the user #1second baseband signal 103_1_2, and the user #2 first baseband signal103_2_1 by using identical times and identical frequencies (bands). Thecombination of modulated signals (baseband signals) for multiple userstransmitted by the transmission apparatus in FIG. 1 is not limited tothe foregoing examples.

Example of Configuration of User #p Signal Processor

Next, a description will be given of the configuration of each of theuser #1 signal processor 102_1 to the user #M signal processor 102_M inFIG. 1 by taking the configuration of the user #p signal processor 102_pas an example. FIG. 2 is a diagram illustrating an example of theconfiguration of the user #p signal processor 102_p.

The user #p signal processor 102_p includes an error-correcting encoder202, a mapper 204, and a signal processor 206.

The error-correcting encoder 202 receives user #p data 201 and a controlsignal 200. The control signal 200 corresponds to the control signal 100in FIG. 1 , and the user #p data 201 corresponds to the user #p data101_p in FIG. 1 . On the basis of information about an error-correctingcode (for example, error-correcting code information, a code length(block length), and a coding rate) included in the control signal 200,the error-correcting encoder 202 performs error-correcting coding, andoutputs user #p coded data 203 to the mapper 204.

The error-correcting encoder 202 may include an interleaver. In a casewhere the error-correcting encoder 202 includes an interleaver, theerror-correcting encoder 202 sorts data after coding the data andoutputs the user #p coded data 203.

The mapper 204 receives the user #p coded data 203 and the controlsignal 200. On the basis of information about a modulation schemeincluded in the control signal 200, the mapper 204 performs mappingcorresponding to the modulation scheme, and generates a user #p mappedsignal (baseband signal) 205_1 and/or mapped signal (baseband signal)205_2. The mapper 204 outputs the generated user #p mapped signal(baseband signal) 205_1 and/or mapped signal (baseband signal) 205_2 tothe signal processor 206.

In a case where the control signal 200 includes information indicatingthat multi-stream transmission is selected, the mapper 204 divides theuser #p coded data 203 into a first sequence and a second sequence.Subsequently, the mapper 204 generates the user #p mapped signal 205_1by using the first sequence and generates the user #p mapped signal205_2 by using the second sequence. At this time, it is assumed that thefirst sequence and the second sequence are different from each other.However, the operation can be performed similarly even if the firstsequence and the second sequence are identical to each other.

In a case where the control signal 200 includes information indicatingthat multi-stream transmission is selected, the mapper 204 may dividethe user #p coded data 203 into three or more sequences, perform mappingby using the individual sequences, and generate three or more mappedsignals. In this case, the three or more sequences may be different fromone another, or some or all of the three or more sequences may beidentical to one another.

In a case where the control signal 200 includes information indicatingthat single-stream transmission is selected, the mapper 204 generatesthe user #p mapped signal 205_1 by using the user #p coded data 203 asone sequence.

The signal processor 206 receives the user #p mapped signal 205_1 and/orthe user #p mapped signal 205_2, a signal group 210, and the controlsignal 200. On the basis of the control signal 200, the signal processor206 performs signal processing, and outputs user #p processed signals207_A and 207_B. The user #p processed signal 207_A corresponds to theuser #p first baseband signal 103_p_1 in FIG. 1 , and the user #pprocessed signal 207_B corresponds to the user #p second baseband signal103_p_2 in FIG. 1 .

At this time, the user #p processed signal 207_A is represented byup1(i), and the user #p processed signal 207_B is represented by up2(i).Here, i is a symbol number and is, for example, an integer equal to orgreater than 0.

Next, the configuration of the signal processor 206 in FIG. 2 will bedescribed with reference to FIG. 3 .

Example of Configuration of Signal Processor 206

FIG. 3 is a diagram illustrating an example of the configuration of thesignal processor 206 in FIG. 2 . The signal processor 206 includes aweight combiner 303, a phase changer 305B, an inserter 307A, an inserter307B, and a phase changer 309B. In FIG. 3 , a description will be givenof a case where the mapper 204 has generated the user #p mapped signal205_1 and the user #p mapped signal 205_2 in FIG. 2 on the basis ofinformation indicating that multi-stream transmission is selected.

The weight combiner (precoder) 303 receives a user #p mapped signal301A, a user #p mapped signal 301B, and a control signal 300. The user#p mapped signal 301A corresponds to the user #p mapped signal 205_1 inFIG. 2 , and the user #p mapped signal 301B corresponds to the user #pmapped signal 205_2 in FIG. 2 . The control signal 300 corresponds tothe control signal 200 in FIG. 2 .

On the basis of the control signal 300, the weight combiner 303 performsweight combining (precoding) and generates a user #p weighted signal304A and a user #p weighted signal 304B. The weight combiner 303 outputsthe user #p weighted signal 304A to the inserter 307A. The weightcombiner 303 outputs the user #p weighted signal 304B to the phasechanger 305B.

The user #p mapped signal 301A is represented by sp1(t), the user #pmapped signal 301B is represented by sp2(t), the user #p weighted signal304A is represented by zp1(t), and the user #p weighted signal 304B isrepresented by zp2′(t). Here, t represents time, for example. Inaddition, sp1(t), sp2(t), zp1(t), and zp2′(t) are defined as complexnumbers. Thus, sp1(t), sp2(t), zp1(t), and zp2′(t) may be real numbers.

In this case, the weight combiner 303 performs computation that is basedon the following Expression (1).

$\begin{matrix}{\begin{pmatrix}{{zp}1(i)} \\{{zp}2^{\prime}(i)}\end{pmatrix} = {\begin{pmatrix}a & b \\c & d\end{pmatrix}\begin{pmatrix}{{sp}1(i)} \\{{sp}2(i)}\end{pmatrix}}} & {{Expression}(1)}\end{matrix}$

In Expression (1), a, b, c, and d are defined as complex numbers, andmay be real numbers. Note that i is a symbol number.

The phase changer 305B receives the weighted signal 304B and the controlsignal 300. On the basis of the control signal 300, the phase changer305B performs phase change on the weighted signal 304B, and outputs aphase-changed signal 306B to the inserter 307B. The phase-changed signal306B is represented by zp2(t). zp2(t) is defined as a complex number,and may be a real number.

A specific operation of the phase changer 305B will be described. It isassumed that the phase changer 305B performs phase change of yp(i) onzp2′(i), for example. This can be expressed by zp2(i)=yp(i)×zp2′(i).Here, i is a symbol number (i is an integer equal to or greater than 0).

For example, the phase changer 305B sets the value of phase changeexpressed as yp(i) as in the following Expression (2).

$\begin{matrix}{{y{p(i)}} = e^{j\frac{2 \times \pi \times i}{N_{p}}}} & {{Expression}(2)}\end{matrix}$

In Expression (2), j is the imaginary unit. In addition, Np is aninteger equal to or greater than 2 and represents the period of phasechange. When Np is set to an odd number equal to or greater than 3, thedata reception quality may be improved. However, Expression (2) ismerely an example, and the value of phase change set in the phasechanger 305B is not limited thereto. Thus, the phase change value isexpressed by yp(i)=e^(j×δp(i)).

At this time, zp1(i) and zp2(i) can be expressed by the followingExpression (3) by using the phase change value yp(i)=e^(j×δp(i)) andExpression (1).

$\begin{matrix}\begin{matrix}{\begin{pmatrix}{{zp}1(i)} \\{{zp}2(i)}\end{pmatrix} = {\begin{pmatrix}1 & 0 \\0 & {y{p(i)}}\end{pmatrix}\begin{pmatrix}{{zp}1(i)} \\{{zp}2^{\prime}(i)}\end{pmatrix}}} \\{= {\begin{pmatrix}1 & 0 \\0 & {y{p(i)}}\end{pmatrix}\begin{pmatrix}a & b \\c & d\end{pmatrix}\begin{pmatrix}{{sp}1(i)} \\{{sp}2(i)}\end{pmatrix}}} \\{= {\begin{pmatrix}1 & 0 \\0 & e^{j \times \delta{p(i)}}\end{pmatrix}\begin{pmatrix}a & b \\c & d\end{pmatrix}\begin{pmatrix}{{sp}1(i)} \\{{sp}2(i)}\end{pmatrix}}}\end{matrix} & {{Expression}(3)}\end{matrix}$

Here, δp(i) is a real number. In addition, zp1(i) and zp2(i) aretransmitted from the transmission apparatus at identical times andidentical frequencies (identical frequency bands).

In Expression (3), the phase change value yp(i) is not limited to thatexpressed by Expression (2). For example, a method of changing the phaseperiodically or regularly may be used.

A description will be given of a matrix used in the computation by theweight combiner 303 expressed by Expression (1) and Expression (3). Thematrix used in the computation by the weight combiner 303 is representedby Fp, as expressed by the following Expression (4).

$\begin{matrix}{\begin{pmatrix}a & b \\c & d\end{pmatrix} = {Fp}} & {{Expression}(4)}\end{matrix}$

For example, any of the matrices expressed by the following Expression(5) to Expression (12) may be used as the matrix Fp.

$\begin{matrix}{{Fp} = \begin{pmatrix}{\beta \times e^{j0}} & {\beta \times \alpha \times e^{j0}} \\{\beta \times \alpha \times e^{j0}} & {\beta \times e^{j\pi}}\end{pmatrix}} & {{Expression}(5)}\end{matrix}$ $\begin{matrix}{{Fp} = {\frac{1}{\sqrt{\alpha^{2} + 1}}\begin{pmatrix}e^{j0} & {\alpha \times e^{j0}} \\{\alpha \times e^{j0}} & e^{j\pi}\end{pmatrix}}} & {{Expression}(6)}\end{matrix}$ $\begin{matrix}{{Fp} = \begin{pmatrix}{\beta \times e^{j0}} & {\beta \times \alpha \times e^{j\pi}} \\{\beta \times \alpha \times e^{j0}} & {\beta \times e^{j0}}\end{pmatrix}} & {{Expression}(7)}\end{matrix}$ $\begin{matrix}{{Fp} = {\frac{1}{\sqrt{\alpha^{2} + 1}}\begin{pmatrix}e^{j0} & {\alpha \times e^{j\pi}} \\{\alpha \times e^{j0}} & e^{j0}\end{pmatrix}}} & {{Expression}(8)}\end{matrix}$ $\begin{matrix}{{Fp} = \begin{pmatrix}{\beta \times \alpha \times e^{j0}} & {\beta \times e^{j\pi}} \\{\beta \times e^{j0}} & {\beta \times \alpha \times e^{j0}}\end{pmatrix}} & {{Expression}(9)}\end{matrix}$ $\begin{matrix}{{Fp} = {\frac{1}{\sqrt{\alpha^{2} + 1}}\begin{pmatrix}{a \times e^{j0}} & e^{j\pi} \\e^{j0} & {\alpha \times e^{j0}}\end{pmatrix}}} & {{Expression}(10)}\end{matrix}$ $\begin{matrix}{{Fp} = \begin{pmatrix}{\beta \times \alpha \times e^{j0}} & {\beta \times e^{j0}} \\{\beta \times e^{j0}} & {\beta \times \alpha \times e^{j\pi}}\end{pmatrix}} & {{Expression}(11)}\end{matrix}$ $\begin{matrix}{{Fp} = {\frac{1}{\sqrt{\alpha^{2} + 1}}\begin{pmatrix}{a \times e^{j0}} & e^{j0} \\e^{j0} & {\alpha \times e^{j\pi}}\end{pmatrix}}} & {{Expression}(12)}\end{matrix}$

In Expression (5) to Expression (12), α may be a real number or animaginary number. Also, β may be a real number or an imaginary number.However, α is not 0 (zero). Also, β is not 0 (zero).

Alternatively, any of the matrices expressed by the following Expression(13) to Expression (20) may be used as the matrix Fp.

$\begin{matrix}{{Fp} = \begin{pmatrix}{\beta \times \cos\theta} & {\beta \times \sin\theta} \\{\beta \times \sin\theta} & {{- \beta} \times \cos\theta}\end{pmatrix}} & {{Expression}(13)}\end{matrix}$ $\begin{matrix}{{Fp} = \begin{pmatrix}{\cos\theta} & {\sin\theta} \\{\sin\theta} & {{- \cos}\theta}\end{pmatrix}} & {{Expression}(14)}\end{matrix}$ $\begin{matrix}{{Fp} = \begin{pmatrix}{\beta \times \cos\theta} & {{- \beta} \times \sin\theta} \\{\beta \times \sin\theta} & {\beta \times \cos\theta}\end{pmatrix}} & {{Expression}(15)}\end{matrix}$ $\begin{matrix}{{Fp} = \begin{pmatrix}{\cos\theta} & {{- \sin}\theta} \\{\sin\theta} & {\cos\theta}\end{pmatrix}} & {{Expression}(16)}\end{matrix}$ $\begin{matrix}{{Fp} = \begin{pmatrix}{\beta \times \sin\theta} & {{- \beta} \times \cos\theta} \\{\beta \times \cos\theta} & {\beta \times \sin\theta}\end{pmatrix}} & {{Expression}(17)}\end{matrix}$ $\begin{matrix}{{Fp} = \begin{pmatrix}{\sin\theta} & {{- \cos}\theta} \\{\cos\theta} & {\sin\theta}\end{pmatrix}} & {{Expression}(18)}\end{matrix}$ $\begin{matrix}{{Fp} = \begin{pmatrix}{\beta \times \sin\theta} & {\beta \times \cos\theta} \\{\beta \times \cos\theta} & {{- \beta} \times \sin\theta}\end{pmatrix}} & {{Expression}(19)}\end{matrix}$ $\begin{matrix}{{Fp} = \begin{pmatrix}{\sin\theta} & {\cos\theta} \\{\cos\theta} & {{- \sin}\theta}\end{pmatrix}} & {{Expression}(20)}\end{matrix}$

In Expression (13) to Expression (20), θ is a real number. In Expression(13), Expression (15), Expression (17), and Expression (19), β may be areal number or an imaginary number. However, β is not 0 (zero).

Alternatively, any of the matrices expressed by the following Expression(21) to Expression (32) may be used as the matrix Fp.

$\begin{matrix}{{{Fp}(i)} = \begin{pmatrix}{\beta \times e^{j{\theta_{11}(i)}}} & {\beta \times \alpha \times e^{j({{\theta_{11}(i)} + \lambda})}} \\{\beta \times \alpha \times e^{j{\theta_{21}(i)}}} & {\beta \times e^{j({{\theta_{21}(i)} + \lambda + \pi})}}\end{pmatrix}} & {{Expression}(21)}\end{matrix}$ $\begin{matrix}{{{Fp}(i)} = {\frac{1}{\sqrt{\alpha^{2} + 1}}\begin{pmatrix}e^{j{\theta_{11}(i)}} & {\alpha \times e^{j({{\theta_{11}(i)} + \lambda})}} \\{\alpha \times e^{j{\theta_{21}(i)}}} & e^{j({{\theta_{21}(i)} + \lambda + \pi})}\end{pmatrix}}} & {{Expression}(22)}\end{matrix}$ $\begin{matrix}{{{Fp}(i)} = \begin{pmatrix}{\beta \times \alpha \times e^{j{\theta_{21}(i)}}} & {\beta \times e^{j({{\theta_{21}(i)} + \lambda + \pi})}} \\{\beta \times e^{j{\theta_{11}(i)}}} & {\beta \times \alpha \times e^{j({{\theta_{11}(i)} + \lambda})}}\end{pmatrix}} & {{Expression}(23)}\end{matrix}$ $\begin{matrix}{{{Fp}(i)} = {\frac{1}{\sqrt{\alpha^{2} + 1}}\begin{pmatrix}{\alpha \times e^{j{\theta_{21}(i)}}} & e^{j({{\theta_{21}(i)} + \lambda + \pi})} \\e^{j{\theta_{11}(i)}} & {\alpha \times e^{j({{\theta_{11}(i)} + \lambda})}}\end{pmatrix}}} & {{Expression}(24)}\end{matrix}$ $\begin{matrix}{{{Fp}(i)} = \begin{pmatrix}{\beta \times e^{j\theta_{11}}} & {\beta \times \alpha \times e^{j({\theta_{11} + {\lambda(i)}})}} \\{\beta \times \alpha \times e^{j\theta_{21}}} & {\beta \times e^{j{({\theta_{21} + {\lambda(i)} + \pi})}}}\end{pmatrix}} & {{Expression}(25)}\end{matrix}$ $\begin{matrix}{{{Fp}(i)} = {\frac{1}{\sqrt{\alpha^{2} + 1}}\begin{pmatrix}e^{j\theta_{11}} & {\alpha \times e^{j({\theta_{11} + {\lambda(i)}})}} \\{\alpha \times e^{j\theta_{21}}} & e^{j({\theta_{21} + {\lambda(i)} + \pi})}\end{pmatrix}}} & {{Expression}(26)}\end{matrix}$ $\begin{matrix}{{{Fp}(i)} = \begin{pmatrix}{\beta \times \alpha \times e^{j\theta_{21}}} & {\beta \times e^{j({\theta_{21} + {\lambda(i)} + \pi})}} \\{\beta \times e^{j\theta_{11}}} & {\beta \times \alpha \times e^{j({\theta_{11} + {\lambda(i)}})}}\end{pmatrix}} & {{Expression}(27)}\end{matrix}$ $\begin{matrix}{{{Fp}(i)} = {\frac{1}{\sqrt{\alpha^{2} + 1}}\begin{pmatrix}{a \times e^{j\theta_{21}}} & e^{j({\theta_{21} + {\lambda(i)} + \pi})} \\e^{j\theta_{11}} & {\alpha \times e^{j({\theta_{11} + {\lambda(i)}})}}\end{pmatrix}}} & {{Expression}(28)}\end{matrix}$ $\begin{matrix}{{Fp} = \begin{pmatrix}{\beta \times e^{j\theta_{11}}} & {\beta \times \alpha \times e^{j({\theta_{11} + \lambda})}} \\{\beta \times \alpha \times e^{j\theta_{21}}} & {\beta \times e^{j({\theta_{21} + \lambda + \pi})}}\end{pmatrix}} & {{Expression}(29)}\end{matrix}$ $\begin{matrix}{{Fp} = {\frac{1}{\sqrt{\alpha^{2} + 1}}\begin{pmatrix}e^{j\theta_{11}} & {\alpha \times e^{j({\theta_{11} + \lambda})}} \\{\alpha \times e^{j\theta_{21}}} & e^{j({\theta_{21} + \lambda + \pi})}\end{pmatrix}}} & {{Expression}(30)}\end{matrix}$ $\begin{matrix}{{Fp} = \begin{pmatrix}{\beta \times \alpha \times e^{j\theta_{21}}} & {\beta \times e^{j({\theta_{21} + \lambda + \pi})}} \\{\beta \times e^{j\theta_{11}}} & {\beta \times \alpha \times e^{j({\theta_{11} + \lambda})}}\end{pmatrix}} & {{Expression}(31)}\end{matrix}$ $\begin{matrix}{{Fp} = {\frac{1}{\sqrt{\alpha^{2} + 1}}\begin{pmatrix}{\alpha \times e^{j\theta_{21}}} & e^{j({\theta_{21} + \lambda + \pi})} \\e^{j\theta_{11}} & {\alpha \times e^{j({\theta_{11} + \lambda})}}\end{pmatrix}}} & {{Expression}(32)}\end{matrix}$

Note that θ₁₁(i), θ₂₁(i), and λ(i) are functions of i (of a symbolnumber) and are real number values. For example, λ is a real numberfixed value. Here, λ need not necessarily be a fixed value. α may be areal number or an imaginary number. β may be a real number or animaginary number. However, α is not 0 (zero). Also, β is not 0 (zero).In addition, θ₁₁ and θ₂₁ are real numbers.

Alternatively, any of the matrices expressed by the following Expression(33) to Expression (36) may be used as the matrix Fp.

$\begin{matrix}{{Fp} = \begin{pmatrix}1 & 0 \\0 & 1\end{pmatrix}} & {{Expression}(33)}\end{matrix}$ $\begin{matrix}{{Fp} = \begin{pmatrix}\beta & 0 \\0 & \beta\end{pmatrix}} & {{Expression}(34)}\end{matrix}$ $\begin{matrix}{{Fp} = \begin{pmatrix}1 & 0 \\0 & {- 1}\end{pmatrix}} & {{Expression}(35)}\end{matrix}$ $\begin{matrix}{{Fp} = \begin{pmatrix}\beta & 0 \\0 & {- \beta}\end{pmatrix}} & {{Expression}(36)}\end{matrix}$

In Expression (34) and Expression (36), β may be a real number or animaginary number. However, β is not 0 (zero).

The individual embodiments can be carried out also by using a precodingmatrix different from those expressed by Expressions (5) to (36) givenabove.

In a case where the precoding matrix Fp is expressed by Expression (33)or Expression (34), the weight combiner 303 in FIG. 3 does not performsignal processing on the mapped signals 301A and 301B and outputs themapped signal 301A as the weighted signal 304A and the mapped signal301B as the weighted signal 304B. That is, the weight combiner 303 neednot necessarily exist. In a case where the weight combiner 303 exists,control of whether or not to perform weight combining may be performedby the control signal 300.

The inserter 307A receives the weighted signal 304A, a pilot symbolsignal (pa(t)) (351A), a preamble signal 352, a control informationsymbol signal 353, and the control signal 300. On the basis ofinformation about a frame configuration included in the control signal300, the inserter 307A outputs a baseband signal 308A that is based onthe frame configuration to the multiplexing signal processor 104.

Likewise, the inserter 307B receives the phase-changed signal 306B, apilot symbol signal (pb(t)) (351B), the preamble signal 352, the controlinformation symbol signal 353, and the control signal 300. On the basisof information about a frame configuration included in the controlsignal 300, the inserter 307B outputs a baseband signal 308B that isbased on the frame configuration to the phase changer 309B.

The generation of control information for generating the controlinformation symbol signal 353 and the frame configuration in thetransmission apparatus used in the inserter 307A and the inserter 307Bwill be described below.

The phase changer 309B receives the baseband signal 308B and the controlsignal 300. On the basis of the control signal 300, the phase changer309B performs phase change on the baseband signal 308B, and outputs aphase-changed signal 310B to the multiplexing signal processor 104.

The baseband signal 308B is regarded as a function of the symbol numberi and is represented by xp′(i). Accordingly, the phase-changed signal310B (xp(i)) output from the phase changer 309B can be expressed byxp(i)=e^(j×εp(i))×xp′(i).

The operation of the phase changer 309B may be Cyclic Delay Diversity(CDD) (Cyclic Shift Diversity (CSD)) described in the followingdocuments: Standard conformable antenna diversity techniques for OFDMand its application to the DVB-T system,” IEEE Globecom 2001, pp.3100-3105, November 2001; and IEEE P802.11n (D3.00) Draft STANDARD forInformation Technology-Telecommunications and information exchangebetween systems-Local and metropolitan area networks-Specificrequirements-Part 11: Wireless LAN Medium Access Control (MAC) andPhysical Layer (PHY) specifications, 2007. A characteristic of the phasechanger 309B is performing phase change on symbols existing in thefrequency-axis direction. The phase changer 309B performs phase changeon data symbols, pilot symbols, control information symbols, and thelike.

FIG. 3 illustrates the signal processor 206 including the phase changer309B, but the phase changer 309B need not necessarily be included in thesignal processor 206. Alternatively, in a case where the phase changer309B is included in the signal processor 206, whether or not the phasechanger 309B operates may be switched. In a case where the phase changer309B is not included in the signal processor 206 or in a case where thephase changer 309B does not operate, the inserter 307B outputs thebaseband signal 308B to the multiplexing signal processor 104 in FIG. 1. In this way, in FIG. 3 , in a case where the phase changer 309B doesnot exist or in a case where the phase changer 309B does not operate,the baseband signal 308B serves as a signal output to the multiplexingsignal processor 104 instead of the phase-changed signal 310B.Hereinafter, a description will be given of, for the convenience ofdescription, a case where the phase changer 309B does not operate.

In a case where weight combining (precoding) processing is performed byusing the (precoding) matrix Fp expressed by Expression (33) orExpression (34), the weight combiner 303 does not perform signalprocessing for weight combining on the mapped signals 301A and 301B, butoutputs the mapped signal 301A as the weighted signal 304A and outputsthe mapped signal 301B as the weighted signal 304B.

In this case, the weight combiner 303 performs, on the basis of thecontrol signal 300, control to switch between processing (i) ofperforming signal processing corresponding to weight combining togenerate and output the weighted signals 304A and 304B, and processing(ii) of not performing signal processing for weight combining, butoutputting the mapped signal 301A as the weighted signal 304A andoutputting the mapped signal 301B as the weighted signal 304B.

In a case where weight combining (precoding) processing is performed byusing only the (precoding) matrix Fp expressed by Expression (33) orExpression (34), the signal processor 206 in FIG. 2 need not necessaryinclude the weight combiner 303.

A description has been given above of a case where the mapper 204 inFIG. 2 generates two sequences of signals in a case where multi-streamtransmission is selected for the user #p. However, in a case wheresingle-stream transmission is selected for the user #p, in FIG. 3 , theweight combiner 303, the phase changer 305B, and the inserter 307B neednot necessarily operate, and the user #p mapped signal 301A may be inputto the inserter 307A without being weighted. Alternatively, in a casewhere single-stream transmission is selected, the user #p signalprocessor 102_p in FIG. 1 need not necessarily include the weightcombiner 303, the phase changer 305B, and the inserter 307B among theelements in FIG. 3 .

A description has been given above of a case where the mapper 204 inFIG. 2 generates two sequences of signals in a case where multi-streamtransmission is selected for the user #p. However, the mapper 204 inFIG. 2 may generate three or more sequences of signals in a case wheremulti-stream transmission is selected for the user #p. In a case wherethe mapper 204 in FIG. 2 generates three or more sequences of signals,the weight combiner 303 in FIG. 3 performs, for example, weightcombining by using a precoding matrix corresponding to the number ofinput signals and outputs three or more weighted signals. The number ofsignals input to the weight combiner 303 in FIG. 3 may be different fromthe number of signals output from the weight combiner 303. That is, theprecoding matrix used in the weight combiner 303 need not necessarily bea square matrix.

In a case where the weight combiner 303 outputs three or more weightedsignals, the signal processor 102_p may perform phase change on all orsome of the three or more weighted signals. Alternatively, the signalprocessor 102_p need not necessarily perform phase change on all of thethree or more weighted signals.

FIG. 4 is a diagram illustrating an example of the configuration of thesignal processor 206 in FIG. 2 , which is different from the example inFIG. 3 . In FIG. 4 , the elements similar to those in FIG. 3 are denotedby the same numerals. The description of the elements similar to thosein FIG. 3 is omitted here.

The signal processor 206 in FIG. 4 has a configuration in which acoefficient multiplier 401A and a coefficient multiplier 401B are addedto the signal processor 206 in FIG. 3 .

The coefficient multiplier 401A receives the mapped signal 301A (sp1(i))and the control signal 300. On the basis of the control signal 300, thecoefficient multiplier 401A multiplies the mapped signal 301A (sp1(i))by a coefficient, and outputs a coefficient-multiplied signal 402A tothe weight combiner 303. When the coefficient is represented by up, thecoefficient-multiplied signal 402A is expressed by up×sp1(i). Here, upmay be a real number or a complex number. However, up is not 0 (zero).In a case where up=1, the coefficient multiplier 401A does not multiplythe mapped signal 301A (sp1(i)) by the coefficient, and outputs themapped signal 301A (sp1(i)) as the coefficient-multiplied signal 402A.

Likewise, the coefficient multiplier 401B receives the mapped signal301B (sp2(i)) and the control signal 300. On the basis of the controlsignal 300, the coefficient multiplier 401B multiplies the mapped signal301B (sp2(i)) by a coefficient, and outputs a coefficient-multipliedsignal 402B to the weight combiner 303. When the coefficient isrepresented by vp, the coefficient-multiplied signal 402B is expressedby vp×sp2(i). Here, vp may be a real number or a complex number.However, vp is not 0 (zero). In a case where vp=1, the coefficientmultiplier 401B does not multiply the mapped signal 301B (sp2(i)) by thecoefficient, and outputs the mapped signal 301B (sp2(i)) as thecoefficient-multiplied signal 402B.

In FIG. 4 , the weighted signal 304A (zp1(i)) output from the weightcombiner 303 and the phase-changed signal 306B (zp2(i)) output from thephase changer 305B are expressed by the following Expression (37) usingthe coefficient up of the coefficient multiplier 401A, the coefficientvp of the coefficient multiplier 401B, and Expression (3).

$\begin{matrix}\begin{matrix}{\begin{pmatrix}{{zp}1(i)} \\{{zp}2(i)}\end{pmatrix} = {\begin{pmatrix}1 & 0 \\0 & {y{p(i)}}\end{pmatrix}F{p\begin{pmatrix}{up} & 0 \\0 & {vp}\end{pmatrix}}\begin{pmatrix}{{sp}1(i)} \\{{sp}2(i)}\end{pmatrix}}} \\{= {\begin{pmatrix}1 & 0 \\0 & {y{p(i)}}\end{pmatrix}\begin{pmatrix}a & b \\c & d\end{pmatrix}\begin{pmatrix}{up} & 0 \\0 & {vp}\end{pmatrix}\begin{pmatrix}{{sp}1(i)} \\{{sp}2(i)}\end{pmatrix}}} \\{= {\begin{pmatrix}1 & 0 \\0 & e^{j \times \delta{p(i)}}\end{pmatrix}\begin{pmatrix}a & b \\c & d\end{pmatrix}\begin{pmatrix}{up} & 0 \\0 & {vp}\end{pmatrix}\begin{pmatrix}{{sp}1(i)} \\{{sp}2(i)}\end{pmatrix}}}\end{matrix} & {{Expression}(37)}\end{matrix}$

Examples of the (precoding) matrix Fp are Expressions (5) to (36) asdescribed above. An example of the phase change value yp(i) is expressedby Expression (2), but the (precoding) matrix Fp and the phase changevalue yp(i) are not limited thereto.

With use of FIG. 1 to FIG. 4 and Expression (1) to Expression (37) as anexample, a description has been given of a method in which the user #psignal processor 102_p generates symbols (for example, zp1(i) andzp2(i)). The generated symbols may be arranged in the time-axisdirection. In the case of using a multi-carrier scheme such asOrthogonal Frequency Division Multiplexing (OFDM), the generated symbolsmay be arranged in the frequency-axis direction or in the time-axis andfrequency-axis directions. In addition, the generated symbols may beinterleaved (i.e., the symbols may be sorted), and arranged in thetime-axis direction, the frequency-axis direction, or the time-axis andfrequency-axis directions.

The symbols are arranged by, for example, the error-correcting encoder202 and/or the mapper 204 illustrated in FIG. 2 in the user #p signalprocessor 102_p.

A method for arranging the symbols will be described below.

The transmission apparatus illustrated in FIG. 1 transmits zp1(i) andzp2(i) having the same symbol number i by using identical times andidentical frequencies (identical frequency bands).

The user #1 baseband signal 103_1_1 in FIG. 1 is zp1(i) when p=1, andthe user #1 baseband signal 103_1_2 is zp2(i) when p=1. Likewise, theuser #2 baseband signal 103_2_1 is zp1(i) when p=2, and the user #2baseband signal 103_2_2 is zp2(i) when p=2. Likewise, the user #Mbaseband signal 103_M_1 is zp1(i) when p=M, and the user #M basebandsignal 103_M_2 is zp2(i) when p=M.

The user #1 signal processor 102_1 generates the user #1 baseband signal103_1_1 and the user #1 baseband signal 103_1_2 by using Expression (3)or Expression (37) Likewise, the user #2 signal processor 102_2generates the user #2 baseband signal 103_2_1 and the user #2 basebandsignal 103_2_2 by using Expression (3) or Expression (37) Likewise, theuser #M signal processor 102_M generates the user #M baseband signal103_M_1 and the user #M baseband signal 103_M_2.

At that time, in the case of generating the user #p baseband signal103_p_1 and the user #p baseband signal 103_p_2 by applying precodingand phase change, the precoding matrix Fp made up of a, b, c, and dand/or the phase change value yp(i) in Expression (3) or Expression (37)are set in accordance with the value of p.

That is, the precoding matrix Fp and/or the phase change value yp(i)used in the user #p signal processor 102_p are set in accordance withthe value of p, that is, for each user. The information for setting theprecoding matrix Fp and/or the phase change value yp(i) is included inthe control signal.

However, not all the user #1 signal processor 102_1 to the user #Msignal processor 102_M in FIG. 1 may apply precoding and phase change.For example, a signal processor that does not perform phase change mayexist among the user #1 signal processor 102_1 to the user #M signalprocessor 102_M. Also, a signal processor that generates one basebandsignal (one stream of a baseband signal) may exist among the user #1signal processor 102_1 to the user #M signal processor 102_M.

As described above, in a case where precoding and phase change areperformed in the user #1 signal processor 102_1 to the user #M signalprocessor 102_M in FIG. 1 as described in the present embodiment, apossibility of being able to avoid falling into a steadily poorreception state in an environment in which direct waves are dominant isincreased. Accordingly, the data reception quality at a terminal can beimproved. In addition, by transmitting modulated signals of multipleusers as in FIG. 1 , the data transmission efficiency of thetransmission apparatus in FIG. 1 increases.

In a case where the control signal 300 includes information indicating“the phase changer 305B does not perform phase change”, the phasechanger 305B does not perform phase change. That is, the phase changer305B may omit phase change for the weighted signal 304B input theretoand may output the weighted signal 304B as 306B.

Example of Multiplexing Signal Processing in Multiplexing SignalProcessor 104

A detailed description will be given of the multiplexing signalprocessing (weight combining processing) in the multiplexing signalprocessor 104 in FIG. 1 .

It is assumed that the user #p first baseband signal 103_p_1 and theuser #p second baseband signal 103_p_2 output from the user #p signalprocessor 102_p (p is an integer from 1 to M) in FIG. 1 are respectivelyrepresented by zp1(i) and zp2(i) on the basis of Expression (3). It isassumed that i is a symbol number and is, for example, an integer equalto or greater than 0. At this time, it is assumed that signalsb{2p−1}(i) and b{2p}(i) are expressed by the following Expressions (38)and (39).

b{2p−1}(i)=zp1(i)  Expression (38)

b{2p}(i)=zp2(i)  Expression (39)

For example, the user #1 first baseband signal 103_1_1 and the user #1second baseband signal 103_1_2 are respectively represented by b{1}(i)and b{2}(i). That is, in a case where each of the user #1 signalprocessor 102_1 to the user #M signal processor 102_M outputs twosignals, the output signals are represented by b{1}(i) to b{2M}(i).

In the case of transmitting a single stream (single modulated signal),either zp1(i) or zp2(i) may be zero.

The multiplexed signal $1 baseband signal 105_1 to the multiplexedsignal $N baseband signal 105_N, which are outputs of the multiplexingsignal processor 104, are respectively represented by v1(i) to vN(i).That is, the multiplexed signal $n baseband signal 105_n is representedby vn(i) (n is an integer from 1 to N). At this time, vn(i) can beexpressed by the following Expression (40).

$\begin{matrix}{{v{n(i)}} = {\sum\limits_{k = 1}^{2M}{\Omega\{ n \}\{ k \} \times b\{ k \}(i)}}} & {{Expression}(40)}\end{matrix}$

At this time, β{n}{k} is a weighted coefficient of multiplexing and canbe defined as a complex number. Thus, β{n}{k} may be a real number. Inaddition, β{n}{k} is decided by feedback information of each terminal.

In the present embodiment, a description is given of, as an example, acase where the user #p signal processor 102_p in FIG. 1 outputs one ortwo modulated signals, but the embodiment is not limited thereto. Theuser #p signal processor 102_p may output three or more modulatedsignals. In this case, the processing of the multiplexing signalprocessor 104 needs to be expressed by an expression different fromExpression (40).

Example of Configuration of Radio Section

The radio section $1 (106_1) to the radio section $N (106_N) in FIG. 1each perform processing such as frequency conversion and amplificationon a signal input thereto and generate a transmission signal, asdescribed above. At this time, in the radio section $1 (106_1) to theradio section $N (106_N), either a single-carrier scheme or amulti-carrier scheme such as the Orthogonal Frequency DivisionMultiplexing (OFDM) scheme may be used. Hereinafter, a description willbe given of, as an example, the radio section $n (106_n) that uses theOFDM scheme.

FIG. 5 is a diagram illustrating an example of the configuration of theradio section $n (106_n) that uses the OFDM scheme. The radio section $n(106_n) includes a serial-parallel converter 502, an inverse Fouriertransform section 504, and a processor 506.

The serial-parallel converter 502 receives a signal 501 and a controlsignal 500. On the basis of the control signal 500, the serial-parallelconverter 502 performs serial-parallel conversion on the signal 501input thereto, and outputs a serial-parallel-converted signal 503 to theinverse Fourier transform section 504. The signal 501 corresponds to themultiplexed signal $n baseband signal 105_n in FIG. 1 , and the controlsignal 500 corresponds to the control signal 100 in FIG. 1 .

The inverse Fourier transform section 504 receives theserial-parallel-converted signal 503 and the control signal 500. On thebasis of the control signal 500, the inverse Fourier transform section504 performs inverse Fourier transform (for example, inverse fastFourier transform (IFFT)) and outputs an inverse-Fourier-transformedsignal 505 to the processor 506.

The processor 506 receives the inverse-Fourier-transformed signal 505and the control signal 500. On the basis of the control signal 500, theprocessor 506 performs processing such as frequency conversion andamplification, and outputs a modulated signal 507 to the antenna section$n (108_n). The modulated signal 507 output from the processor 506corresponds to the transmission signal 107_n in FIG. 1 .

Example of Configuration of Antenna Section

FIG. 6 is a diagram illustrating an example of the configuration of eachof the antenna sections (the antenna section $1 (108_1) to the antennasection $N (108_N)) in FIG. 1 . The configuration in FIG. 6 is anexample in which the antenna section $1 (108_1) to the antenna section$N (108_N) are each constituted by four antennas. The antenna sectionincludes a distributor 902, multipliers 904_1 to 904_4, and antennas906_1 to 906_4.

The distributor 902 receives a transmission signal 901. The distributor902 distributes the transmission signal 901 and outputs transmissionsignals 903_1, 903_2, 903_3, and 903_4 to the corresponding multipliers(the multiplier 904_1 to the multiplier 904_4).

When the antenna section $1 (108_1) in FIG. 1 has the configuration inFIG. 6 , the transmission signal 901 corresponds to the transmissionsignal 107_1 in FIG. 1 . When the antenna section $2 (108_2) in FIG. 1has the configuration in FIG. 6 , the transmission signal 901corresponds to the transmission signal 107_2 in FIG. 1 . When theantenna section $N (108_N) in FIG. 1 has the configuration in FIG. 6 ,the transmission signal 901 corresponds to the transmission signal 107_Nin FIG. 1 .

The multiplier 904_1 receives the transmission signal 903_1 and acontrol signal 900. On the basis of information about a multiplicationcoefficient included in the control signal 900, the multiplier 904_1multiplies the transmission signal 903_1 by the multiplicationcoefficient, and outputs a multiplied signal 905_1 to the antenna 906_1.The multiplied signal 905_1 is output as a radio wave from the antenna906_1.

When the transmission signal 903_1 is represented by Tx1(t) (t is time)and the multiplication coefficient is represented by W1, the multipliedsignal 905_1 is expressed by Tx1(t)×W1. Here, W1 can be defined as acomplex number and thus may be a real number.

The multiplier 904_2 receives the transmission signal 903_2 and thecontrol signal 900. On the basis of information about a multiplicationcoefficient included in the control signal 900, the multiplier 904_2multiplies the transmission signal 903_2 by the multiplicationcoefficient, and outputs a multiplied signal 905_2 to the antenna 906_2.The multiplied signal 905_2 is output as a radio wave from the antenna906_2.

When the transmission signal 903_2 is represented by Tx2(t) and themultiplication coefficient is represented by W2, the multiplied signal905_2 is expressed by Tx2(t)×W2. Here, W2 can be defined as a complexnumber and thus may be a real number.

The multiplier 904_3 receives the transmission signal 903_3 and thecontrol signal 900. On the basis of information about a multiplicationcoefficient included in the control signal 900, the multiplier 904_3multiplies the transmission signal 903_3 by the multiplicationcoefficient, and outputs a multiplied signal 905_3 to the antenna 906_3.The multiplied signal 905_3 is output as a radio wave from the antenna906_3.

When the transmission signal 903_3 is represented by Tx3(t) and themultiplication coefficient is represented by W3, the multiplied signal905_3 is expressed by Tx3(t)×W3. Here, W3 can be defined as a complexnumber and thus may be a real number.

The multiplier 904_4 receives the transmission signal 903_4 and thecontrol signal 900. On the basis of information about a multiplicationcoefficient included in the control signal 900, the multiplier 904_4multiplies the transmission signal 903_4 by the multiplicationcoefficient, and outputs a multiplied signal 905_4 to the antenna 906_4.The multiplied signal 905_4 is output as a radio wave from the antenna906_4.

When the transmission signal 903_4 is represented by Tx4(t) and themultiplication coefficient is represented by W4, the multiplied signal905_4 is expressed by Tx4(t)×W4. Here, W4 can be defined as a complexnumber and thus may be a real number.

Here, “the absolute value of W1, the absolute value of W2, the absolutevalue of W3, and the absolute value of W4 may be equal”. Thiscorresponds to a state where phase change has been performed. Obviously,the absolute value of W1, the absolute value of W2, the absolute valueof W3, and the absolute value of W4 may be unequal.

In FIG. 6 , a description is given of an example in which each antennasection is constituted by four antennas (and four multipliers). However,the number of antennas is not limited four, and it is sufficient thateach antenna section be constituted by one or more antennas.

In addition, the antenna section $1 (108_1) to the antenna section $N(108_N) each need not necessarily have the configuration as in FIG. 6 ,and the antenna section need not necessarily receive the control signal100, as described above. For example, each of the antenna section $1(108_1) to the antenna section $N (108_N) in FIG. 1 may be constitutedby one antenna or multiple antennas.

Generation of Control Information

FIG. 7 is a diagram illustrating an example of the configuration of aportion related to control information generation for generating thecontrol information symbol signal 353 in FIGS. 3 and 4 .

A control information mapper 802 receives control information-relateddata 801 and a control signal 800. The control information mapper 802performs mapping on the control information-related data 801 by using amodulation scheme that is based on the control signal 800, and outputs acontrol information mapped signal 803. The control information mappedsignal 803 corresponds to the control information symbol signal 353 inFIGS. 3 and 4 .

First Example of Frame Configuration in Transmission Apparatus

Next, a frame configuration in the transmission apparatus will bedescribed. The frame configuration shows the arrangement of datasymbols, pilot symbols, and other symbols to be transmitted. Informationabout the frame configuration is included in the control signal 300 (seeFIGS. 3 and 4 ). The inserter 307A and the inserter 307B illustrated inFIGS. 3 and 4 respectively generate the baseband signal 308A and thebaseband signal 308B that are based on the frame configuration.

Hereinafter, an example is given in which a multi-carrier transmissionscheme such as OFDM is used, the inserter 307A in the user #p signalprocessor 102_p outputs the user #p first baseband signal 103_p_1 inFIG. 1 as the baseband signal 308A, and the inserter 307B outputs theuser #p second baseband signal 103_p_2 in FIG. 1 as the baseband signal308B. The frame configurations of the user #p first baseband signal103_p_1 and the user #p second baseband signal 103_p_2 in this case willbe described as an example.

FIG. 8 is a diagram illustrating an example of the frame configurationof the user #p first baseband signal 103_p_1. In FIG. 8 , the horizontalaxis indicates frequency (carrier), and the vertical axis indicatestime. Since a multi-carrier transmission scheme such as OFDM is used,symbols exist in the carrier direction. FIG. 8 illustrates, as anexample, symbols from carrier 1 to carrier 36. In addition, FIG. 8illustrates symbols from time 1 to time 11.

In FIG. 8, 601 denotes a pilot symbol (the pilot symbol signal 351A(corresponding to pa(t)) in FIGS. 3 and 4 ), 602 denotes a data symbol,and 603 denotes another symbol. At this time, the pilot symbols arePhase Shift Keying (PSK) symbols, for example, and are symbols used by areception apparatus that receives this frame to perform channelestimation (estimation of propagation path variation) and estimation offrequency offset/phase variation. For example, the transmissionapparatus in FIG. 1 and the reception apparatus that receives a signalhaving the frame configuration in FIG. 8 may preferably share a methodfor transmitting the pilot symbols.

Here, the user #p mapped signal 205_1 is called “stream #1”, and theuser #p mapped signal 205_2 is called “stream #2”. The same applies tothe description given below.

The data symbols 602 are symbols corresponding to the data symbolsincluded in the baseband signal 207_A generated in FIG. 2 . Thus, thedata symbols 602 are any of “symbols including both the symbols of“stream #1” and the symbols of “stream #2”, “the symbols of “stream#1””, and “the symbols of “stream #2””. This is decided by theconfiguration of the precoding matrix used by the weight combiner 303 inFIG. 3 . That is, the data symbols 602 correspond to the weighted signal304A (zp1(i)).

The other symbols 603 are symbols corresponding to the preamble signal352 and the control information symbol signal 353 in FIGS. 3 and 4 .However, the other symbols may include symbols other than a preamble andcontrol information symbols. At this time, the preamble may transmitdata (for control), and are made up of symbols for signal detection,symbols for performing frequency synchronization/time synchronization,symbols for channel estimation (symbols for estimating propagation pathvariation), and so forth. The control information symbols are symbolsincluding control information that is used by the reception apparatusthat has received the frame in FIG. 8 to demodulate and decode the datasymbols.

For example, carrier 1 to carrier 36 from time 1 to time 4 in FIG. 8correspond to the other symbols 603. Carrier 1 to carrier 11 at time 5correspond to the data symbols 602. In the following, carrier 12 at time5 corresponds to the pilot symbol 601, carrier 13 to carrier 23 at time5 correspond to the data symbols 602, carrier 24 at time 5 correspondsto the pilot symbol 601, carrier 1 and carrier 2 at time 6 correspond tothe data symbols 602, carrier 3 at time 6 corresponds to the pilotsymbol 601, carrier 30 at time 11 corresponds to the pilot symbol 601,and carrier 31 to carrier 36 at time 11 correspond to the data symbols602.

FIG. 9 is a diagram illustrating an example of the frame configurationof the user #p second baseband signal 103_p_2. In FIG. 9 , thehorizontal axis indicates frequency (carrier), and the vertical axisindicates time. Since a multi-carrier transmission scheme such as OFDMis used, symbols exist in the carrier direction. FIG. 9 illustrates, asan example, symbols from carrier 1 to carrier 36. In addition, FIG. 9illustrates symbols from time 1 to time 11.

In FIG. 9, 701 denotes a pilot symbol (the pilot symbol signal 351B(corresponding to pb(t)) in FIGS. 3 and 4 ), 702 denotes a data symbol,and 703 denotes an other symbol. At this time, the pilot symbols are PSKsymbols, for example, and are symbols used by a reception apparatus thatreceives this frame to perform channel estimation (estimation ofpropagation path variation) and estimation of frequency offset/phasevariation. For example, the transmission apparatus in FIG. 1 and thereception apparatus that receives a signal having the frameconfiguration in FIG. 9 may preferably share a method for transmittingthe pilot symbols.

The data symbols 702 are symbols corresponding to the data symbolsincluded in the baseband signal 207_B generated in FIG. 2 . Thus, thedata symbols 702 are any of “symbols including both the symbols of“stream #1” and the symbols of “stream #2”, “the symbols of “stream#1””, and “the symbols of “stream #2””. Which symbols among the abovethree are to be used is decided by the configuration of the precodingmatrix used by the weight combiner 303 in FIG. 3 . That is, the datasymbols 702 correspond to the phase-changed signal 306B (zp2(i)).

The other symbols 703 are symbols corresponding to the preamble signal352 and the control information symbol signal 353 in FIGS. 3 and 4 .However, the other symbols may include symbols other than a preamble andcontrol information symbols. At this time, the preamble may transmitdata (for control), and are made up of symbols for signal detection,symbols for performing frequency synchronization/time synchronization,symbols for channel estimation (symbols for estimating propagation pathvariation), and so forth. The control information symbols are symbolsincluding control information that is used by the reception apparatusthat has received the frame in FIG. 9 to demodulate and decode the datasymbols.

For example, carrier 1 to carrier 36 from time 1 to time 4 in FIG. 9correspond to the other symbols 703. Carrier 1 to carrier 11 at time 5correspond to the data symbols 702. In the following, carrier 12 at time5 corresponds to the pilot symbol 701, carrier 13 to carrier 23 at time5 correspond to the data symbols 702, carrier 24 at time 5 correspondsto the pilot symbol 701, carrier 1 and carrier 2 at time 6 correspond tothe data symbols 702, carrier 3 at time 6 corresponds to the pilotsymbol 701, carrier 30 at time 11 corresponds to the pilot symbol 701,and carrier 31 to carrier 36 at time 11 correspond to the data symbols702.

When a symbol exists at carrier A and time B in FIG. 8 and a symbolexists at carrier A and time B in FIG. 9 , the symbol at carrier A andtime B in FIG. 8 and the symbol at carrier A and time B in FIG. 9 aretransmitted at identical times and identical frequencies. The frameconfiguration is not limited to those in FIGS. 8 and 9 . The frameconfigurations in FIGS. 8 and 9 are merely examples.

The other symbols 603 and 703 in FIGS. 8 and 9 are symbols correspondingto “the preamble signal 352 and the control information symbol signal353 in FIGS. 3 and 4 ”. Thus, in a case where the other symbols 603 inFIG. 8 and the other symbols 703 in FIG. 9 at the identical times andidentical frequencies (identical carriers) are transmitting controlinformation, identical data (identical control information) is beingtransmitted.

The reception apparatus expects to simultaneously receive the frame inFIG. 8 and the frame in FIG. 9 . However, the reception apparatus isable to obtain data transmitted by the transmission apparatus even ifthe reception apparatus receives only the frame in FIG. 8 or only theframe in FIG. 9 .

In a case where the user #1 signal processor 102_1 in FIG. 1 outputs thefirst baseband signal 103_1_1 and the second baseband signal 103_1_2,the first baseband signal 103_1_1 and the second baseband signal 103_1_2respectively have the frame configurations in FIGS. 8 and 9 . Likewise,in a case where the user #2 signal processor 102_2 in FIG. 1 outputs thefirst baseband signal 103_2_1 and the second baseband signal 103_2_2,the first baseband signal 103_2_1 and the second baseband signal 103_2_2respectively have the frame configurations in FIGS. 8 and 9 . Likewise,in a case where the user #M signal processor 102_M in FIG. 1 outputs thefirst baseband signal 103_M_1 and the second baseband signal 103_M_2,the first baseband signal 103_M_1 and the second baseband signal 103_M_2respectively have the frame configurations in FIGS. 8 and 9 . SecondExample of Frame Configuration in Transmission apparatus

In FIGS. 8 and 9 , a description has been given of a frame configurationin a case where a multi-carrier transmission scheme such as OFDM isused. Now, a description will be given of a frame configuration in thetransmission apparatus in a case where a single-carrier scheme is used.

FIG. 10 is a diagram illustrating another example of the frameconfiguration of the user #p first baseband signal 103_p_1. In FIG. 10 ,the horizontal axis indicates time. The difference between FIGS. 10 and8 is that the frame configuration in FIG. 10 is an example of the frameconfiguration for a single-carrier scheme and symbols exist in the timedirection. In addition, FIG. 10 illustrates symbols from time t1 to t22.

A preamble 1001 in FIG. 10 corresponds to the preamble signal 352 inFIGS. 3 and 4 . At this time, the preamble may transmit data (forcontrol), and may be made up of symbols for signal detection, symbolsfor performing frequency synchronization/time synchronization, symbolsfor performing channel estimation (symbols for estimating propagationpath variation), and so forth.

A control information symbol 1002 in FIG. 10 is a symbol correspondingto the control information symbol signal 353 in FIGS. 3 and 4 , and is asymbol including control information that is used by the receptionapparatus that has received a signal having the frame configuration inFIG. 10 to demodulate and decode data symbols.

A pilot symbol 1004 in FIG. 10 is a symbol corresponding to the pilotsignal 351A (pa(t)) in FIGS. 3 and 4 . The pilot symbol 1004 is a PSKsymbol, for example, and is a symbol that is used by the receptionapparatus that receives this frame to perform channel estimation(estimation of propagation path variation) and estimation of frequencyoffset/estimation of phase variation. For example, the transmissionapparatus in FIG. 1 and the reception apparatus that receives a signalhaving the frame configuration in FIG. 10 may preferably share a methodfor transmitting the pilot symbol.

In FIG. 10, 1003 denotes data symbols for transmitting data.

The user #p mapped signal 205_1 is called “stream #1”, and the user #pmapped signal 205_2 is called “stream #2”.

The data symbols 1003 are symbols corresponding to the data symbolsincluded in the baseband signal 207_A generated in FIG. 2 . Thus, thedata symbols 1003 are any symbols among three candidates: “symbolsincluding both the symbols of “stream #1” and the symbols of “stream#2”, “the symbols of “stream #1””, and “the symbols of “stream #2”.Which symbols among the above three are to be used is decided by theconfiguration of the precoding matrix used by the weight combiner 303 inFIG. 3 . That is, the data symbols 1003 correspond to the weightedsignal 304A (zp1(i)).

For example, it is assumed that the transmission apparatus transmits thepreamble 1001 at time t1 in FIG. 10 , transmits the control informationsymbol 1002 at time t2, transmits the data symbols 1003 from time t3 tot11, transmits the pilot symbol 1004 at time t12, transmits the datasymbols 1003 from time t13 to t21, and transmits the pilot symbol 1004at time t22.

Although not illustrated in FIG. 10 , the frame may include symbolsother than the preamble, the control information symbol, the datasymbols, and the pilot symbols. In addition, the frame need notnecessarily include all of the preamble, the control information symbol,and the pilot symbols.

FIG. 11 is a diagram illustrating another example of the frameconfiguration of the user #p second baseband signal 103_p_2. In FIG. 11, the horizontal axis indicates time. The difference between FIGS. 11and 9 is that the frame configuration in FIG. 11 is an example of theframe configuration for a single-carrier scheme and symbols exist in thetime direction. In addition, FIG. 11 illustrates symbols from time t1 tot22.

A preamble 1101 in FIG. 11 corresponds to the preamble signal 352 inFIGS. 3 and 4 . At this time, the preamble may transmit data (forcontrol), and may be made up of symbols for signal detection, symbolsfor performing frequency synchronization/time synchronization, symbolsfor performing channel estimation (symbols for estimating propagationpath variation), and so forth.

A control information symbol 1102 in FIG. 11 is a symbol correspondingto the control information symbol signal 353 in FIGS. 3 and 4 , and is asymbol including control information that is used by the receptionapparatus that has received a signal having the frame configuration inFIG. 11 to demodulate and decode data symbols.

A pilot symbol 1104 in FIG. 11 is a symbol corresponding to the pilotsignal 351B (pb(t)) in FIGS. 3 and 4 . The pilot symbol 1104 is a PSKsymbol, for example, and is a symbol that is used by the receptionapparatus that receives this frame to perform channel estimation(estimation of propagation path variation) and estimation of frequencyoffset/estimation of phase variation. For example, the transmissionapparatus in FIG. 1 and the reception apparatus that receives a signalhaving the frame configuration in FIG. 11 may preferably share a methodfor transmitting the pilot symbol.

In FIG. 11, 1103 denotes data symbols for transmitting data.

The user #p mapped signal 205_1 is called “stream #1”, and the user #pmapped signal 205_2 is called “stream #2”

The data symbols 1103 are symbols corresponding to the data symbolsincluded in the baseband signal 207_B generated in FIG. 2 . Thus, thedata symbols 1103 are any symbols among three candidates: “symbolsincluding both the symbols of “stream #1” and the symbols of “stream#2”, “the symbols of “stream #1””, and “the symbols of “stream #2”.Which symbols among the above three are to be used is decided by theconfiguration of the precoding matrix used by the weight combiner 303 inFIG. 3 . That is, the data symbols 1103 correspond to the phase-changedsignal 306B (zp2(i)).

For example, it is assumed that the transmission apparatus transmits thepreamble 1101 at time t1 in FIG. 11 , transmits the control informationsymbol 1102 at time t2, transmits the data symbols 1103 from time t3 tot11, transmits the pilot symbol 1104 at time t12, transmits the datasymbols 1103 from time t13 to t21, and transmits the pilot symbol 1104at time t22.

Although not illustrated in FIG. 11 , the frame may include symbolsother than the preamble, the control information symbol, the datasymbols, and the pilot symbols. In addition, the frame need notnecessarily include all of the preamble, the control information symbol,and the pilot symbols.

When a symbol exists at time tz in FIG. 10 and a symbol exists at timetz in FIG. 11 (z is an integer equal to or greater than 1), the symbolat time tz in FIG. 10 and the symbol at time tz in FIG. 11 aretransmitted at identical times and identical frequencies. For example,the data symbol at time t3 in FIG. 10 and the data symbol at time t3 inFIG. 11 are transmitted at identical times and identical frequencies.The frame configuration is not limited to those in FIGS. 10 and 11 . Theframe configurations in FIGS. 10 and 11 are merely examples.

The preamble and the control information symbol in FIGS. 10 and 11 maytransmit identical data (identical control information).

The reception apparatus expects to simultaneously receive the frame inFIG. 10 and the frame in FIG. 11 . However, the reception apparatus isable to obtain data transmitted by the transmission apparatus even ifthe reception apparatus receives only the frame in FIG. 10 or only theframe in FIG. 11 .

In a case where the user #1 signal processor 102_1 in FIG. 1 outputs thefirst baseband signal 103_1_1 and the second baseband signal 103_1_2,the first baseband signal 103_1_1 and the second baseband signal 103_1_2respectively have the frame configurations in FIGS. 10 and 11 .Likewise, in a case where the user #2 signal processor 102_2 in FIG. 1outputs the first baseband signal 103_2_1 and the second baseband signal103_2_2, the first baseband signal 103_2_1 and the second basebandsignal 103_2_2 respectively have the frame configurations in FIGS. 10and 11 . Likewise, in a case where the user #M signal processor 102_M inFIG. 1 outputs the first baseband signal 103_M_1 and the second basebandsignal 103_M_2, the first baseband signal 103_M_1 and the secondbaseband signal 103_M_2 respectively have the frame configurations inFIGS. 10 and 11 .

Method for Arranging Symbols

Next, a description will be given of a method for arranging symbols inthe present embodiment. Symbols are sorted with respect to the frequencyaxis and/or the time axis by an interleaver. For example, symbols arearranged by the error-correcting encoder 202 and/or the mapper 204illustrated in FIG. 2 in the user #p signal processor 102_p.

FIG. 12 is a diagram illustrating an example of a method for arrangingsymbols of the weighted signal 304A (zp1(i)) and the phase-changedsignal 306B (zp2(i)) with respect to the time axis.

In FIG. 12 , a symbol is denoted by zpq(0). At this time, q is 1 or 2.Thus, zpq(0) in FIG. 12 represents “in zp1(i) and zp2(i), zp1(0) andzp2(0) when the symbol number i=0” Likewise, zpq(1) represents “inzp1(i) and zp2(i), zp1(1) and zp2(1) when the symbol number i=1”. Thatis, zpq(X) represents “in zp1(i) and zp2(i), zp1(X) and zp2(X) when thesymbol number i=X”. The same applies to FIGS. 13, 14, and 15 .

In the example in FIG. 12 , the symbol zpq(0) with the symbol number i=0is arranged at time 0, the symbol zpq(1) with the symbol number i=1 isarranged at time 1, the symbol zpq(2) with the symbol number i=2 isarranged at time 2, and the symbol zpq(3) with the symbol number i=3 isarranged at time 3. In this way, symbols of the weighted signal 304A(zp1(i)) and the phase-changed signal 306B (zp2(i)) are arranged withrespect to the time axis. However, FIG. 12 is an example, and therelationship between the symbol number and time is not limited thereto.

FIG. 13 is a diagram illustrating an example of a method for arrangingsymbols of the weighted signal 304A (zp1(i)) and the phase-changedsignal 306B (zp2(i)) with respect to the frequency axis.

In the example in FIG. 13 , the symbol zpq(0) with the symbol number i=0is arranged at carrier 0, the symbol zpq(1) with the symbol number i=1is arranged at carrier 1, the symbol zpq(2) with the symbol number i=2is arranged at carrier 2, and the symbol zpq(3) with the symbol numberi=3 is arranged at carrier 3. In this way, symbols of the weightedsignal 304A (zp1(i)) and the phase-changed signal 306B (zp2(i)) arearranged with respect to the frequency axis. However, FIG. 13 is anexample, and the relationship between the symbol number and frequency isnot limited thereto.

FIG. 14 is a diagram illustrating an example of the arrangement ofsymbols of the weighted signal 304A (zp1(i)) and the phase-changedsignal 306B (zp2(i)) with respect to the time and frequency axes.

In the example in FIG. 14 , the symbol zpq(0) with the symbol number i=0is arranged at time 0 and carrier 0, the symbol zpq(1) with the symbolnumber i=1 is arranged at time 0 and carrier 1, the symbol zpq(2) withthe symbol number i=2 is arranged at time 1 and carrier 0, and thesymbol zpq(3) with the symbol number i=3 is arranged at time 1 andcarrier 1. In this way, symbols of the weighted signal 304A (zp1(i)) andthe phase-changed signal 306B (zp2(i)) are arranged with respect to thetime and frequency axes. However, FIG. 14 is an example, and therelationship between the symbol number and time/frequency is not limitedthereto.

FIG. 15 is a diagram illustrating an example of the arrangement ofsymbols of the weighted signal 304A (zp1(i)) and the phase-changedsignal 306B (zp2(i)) with respect to the time axis.

In the example in FIG. 15 , the symbol zpq(0) with the symbol number i=0is arranged at time 0, the symbol zpq(1) with the symbol number i=1 isarranged at time 16, the symbol zpq(2) with the symbol number i=2 isarranged at time 12, and the symbol zpq(3) with the symbol number i=3 isarranged at time 5. In this way, symbols of the weighted signal 304A(zp1(i)) and the phase-changed signal 306B (zp2(i)) in FIG. 3 arearranged with respect to the time axis. That is, in the example in FIG.15 , the symbols are sorted in the time-axis direction. However, FIG. 15is an example, and the relationship between the symbol number and timeis not limited thereto.

In FIG. 15 , each symbol is denoted by zpq(i), which may be a symbolgenerated by multiplexing signals directed to multiple users by themultiplexing signal processor 104 in FIG. 1 . In addition, the examplein FIG. 15 may be the arrangement of symbols in a case where each of theradio section $1 (106_1) to the radio section $N (106_N) in FIG. 1includes an interleaver (a section that sorts symbols) and eachinterleaver sorts symbols. The position where interleaving is performedis not limited to the user signal processor or the radio section.

FIG. 16 is a diagram illustrating an example of the arrangement ofsymbols of the weighted signal 304A (zp1(i)) and the phase-changedsignal 306B (zp2(i)) with respect to the frequency axis.

In the example in FIG. 16 , the symbol zpq(0) with the symbol number i=0is arranged at carrier 0, the symbol zpq(1) with the symbol number i=1is arranged at carrier 16, the symbol zpq(2) with the symbol number i=2is arranged at carrier 12, and the symbol zpq(3) with the symbol numberi=3 is arranged at carrier 5. In this way, symbols of the weightedsignal 304A (zp1(i)) and the phase-changed signal 306B (zp2(i)) in FIG.3 are arranged with respect to the frequency axis. However, FIG. 16 isan example, and the relationship between the symbol number and frequencyis not limited thereto.

In FIG. 16 , each symbol is denoted by zpq(i), which may be a symbolgenerated by multiplexing signals directed to multiple users by themultiplexing signal processor 104 in FIG. 1 . In addition, the examplein FIG. 16 may be the arrangement of symbols in a case where each of theradio section $1 (106_1) to the radio section $N (106_N) in FIG. 1includes an interleaver (a section that sorts symbols) and eachinterleaver sorts symbols. The position where interleaving is performedis not limited to the user signal processor or the radio section.

FIG. 17 is a diagram illustrating an example of the arrangement ofsymbols of the weighted signal 304A (zp1(i)) and the phase-changedsignal 306B (zp2(i)) with respect to the time and frequency axes.

In the example in FIG. 17 , the symbol zpq(0) with the symbol number i=0is arranged at time 1 and carrier 1, the symbol zpq(1) with the symbolnumber i=1 is arranged at time 3 and carrier 3, the symbol zpq(2) withthe symbol number i=2 is arranged at time 1 and carrier 0, and thesymbol zpq(3) with the symbol number i=3 is arranged at time 1 andcarrier 3. In this way, symbols of the weighted signal 304A (zp1(i)) andthe phase-changed signal 306B (zp2(i)) in FIG. 3 are arranged withrespect to the time and frequency axes. However, FIG. 17 is an example,and the relationship between the symbol number and time/frequency is notlimited thereto.

In FIG. 17 , each symbol is denoted by zpq(i), which may be a symbolgenerated by multiplexing signals directed to multiple users by themultiplexing signal processor 104 in FIG. 1 . In addition, the examplein FIG. 17 may be the arrangement of symbols in a case where each of theradio section $1 (106_1) to the radio section $N (106_N) in FIG. 1includes an interleaver (a section that sorts symbols) and eachinterleaver sorts symbols. The position where interleaving is performedis not limited to the user signal processor or the radio section.

According to the description given above, the arrangement of symbols isperformed by, for example, the error-correcting encoder 202 and/or themapper 204 illustrated in FIG. 2 in the user #p signal processor 102_p,but the embodiment is not limited thereto. As described above, each ofthe radio section $1 (106_1) to the radio section $N (106_N) in FIG. 1may include an interleaver (a section that sorts symbols) and eachinterleaver may sort symbols. Alternatively, the multiplexing signalprocessor 104 may include an interleaver, and the interleaver mayperform the arrangement of symbols illustrated in FIGS. 12 to 17 .Hereinafter, a description will be given of the multiplexing signalprocessor 104 that includes an interleaver with reference to FIG. 18 .

Another Example of Configuration of Multiplexing Signal Processor

FIG. 18 is a diagram illustrating the configuration of the multiplexingsignal processor 104 in FIG. 1 that includes an interleaver (a sectionthat sorts symbols).

A user #1 interleaver (sorter) 1802_1 receives processed signals1801_1_1 and 1801_1_2 and a control signal 1800. The processed signals1801_1_1 and 1801_1_2 respectively correspond to the user #1 firstbaseband signal 103_1_1 and the user #1 second baseband signal 103_1_2in FIG. 1 . The control signal 1800 corresponds to the control signal100 in FIG. 1 .

In accordance with the control signal 1800, the user #1 interleaver(sorter) 1802_1 sorts symbols as in FIGS. 12 to 17 , and outputs user #1sorted signals 1803_1 and 1803_2, for example.

The multiplexing signal processor 104 also includes a user #2interleaver to a user #M interleaver. The user #2 interleaver to theuser #M interleaver each have a function similar to that of the user #1interleaver 1802_1.

A signal processor 1804 receives the control signal 1800, the user #1sorted signals 1803_1 and 1803_2, and so forth. The signal processor1804 also receives sorted signals for other users. In accordance withthe control signal 1800, the signal processor 1804 performs signalprocessing such as the weight combining described above on the sortedsignals and outputs a multiplexed signal $1 baseband signal 1805_1 to amultiplexed signal $N baseband signal 1805_N. The multiplexed signal $1baseband signal 1805_1 to the multiplexed signal $N baseband signal1805_N respectively correspond to the multiplexed signal $1 basebandsignal 105_1 to the multiplexed signal $N baseband signal 105_N in FIG.1 .

An example of the transmission apparatus according to the presentembodiment has been described above. Next, an example of theconfiguration of the reception apparatus according to the presentembodiment will be described.

Example of Configuration of Reception Apparatus

FIG. 19 is a diagram illustrating an example of the configuration of thereception apparatus according to the present embodiment. The receptionapparatus in FIG. 19 is a reception apparatus of a terminalcorresponding to a user #p among a user #1 to a user #M that receivemodulated signals when the transmission apparatus in FIG. 1 transmits,for example, transmission signals having the frame configurations inFIGS. 8 and 9 or transmission signals having the frame configurations inFIGS. 10 and 11 .

A radio section 1903X receives a reception signal 1902X received by anantenna section #X (1901X). The radio section 1903X performs receptionprocessing such as frequency conversion and Fourier transform, andoutputs a baseband signal 1904X to a modulated signal u1 channelestimator 1905_1 and a modulated signal u2 channel estimator 1905_2.

Likewise, a radio section 1903Y receives a reception signal 1902Yreceived by an antenna section #Y (1901Y). The radio section 1903Yperforms reception processing such as frequency conversion and Fouriertransform, and outputs a baseband signal 1904Y.

FIG. 19 illustrates a configuration in which a control signal 1910 isinput to the antenna section #X (1901X) and the antenna section #Y(1901Y), but the control signal 1910 need not necessarily be inputthereto. The configuration of an antenna section in a case where thecontrol signal 1910 exists as input will be described below.

The modulated signal u1 channel estimator 1905_1 and the modulatedsignal u2 channel estimator 1905_2 perform channel estimation on thebasis of the baseband signal 1904X. A modulated signal u1 channelestimator 1907_1 and a modulated signal u2 channel estimator 1907_2perform channel estimation on the basis of the baseband signal 1904Y.The channel estimation will be described with reference to FIG. 20 .

FIG. 20 is a diagram illustrating the relationship between thetransmission apparatus and the reception apparatus. Antennas 2001_1 and2001_2 in FIG. 20 are transmission antennas. The antenna 2001_1 in FIG.20 corresponds to, for example, the antenna section in FIG. 1 used totransmit a transmission signal u1(i). Also, the antenna 2001_2 in FIG.20 corresponds to, for example, the antenna section in FIG. 1 used totransmit a transmission signal u2(i). The correspondence between FIGS.20 and 1 is not limited thereto.

Antennas 2002_1 and 2002_2 in FIG. 20 are reception antennas. Theantenna 2002_1 in FIG. 20 corresponds to the antenna section #X (1901X)in FIG. 19 . The antenna 2002_2 in FIG. 20 corresponds to the antennasection #Y (1901Y) in FIG. 19 .

As in FIG. 20 , the signal transmitted from the transmission antenna2001_1 is represented by u1(i), the signal transmitted from thetransmission antenna 2001_2 is represented by u2(i), the signal receivedby the reception antenna 2002_1 is represented by r1(i), and the signalreceived by the reception antenna 2002_2 is represented by r2(i). Here,i represents a symbol number and is, for example, an integer equal to orgreater than 0.

In addition, a propagation coefficient from the transmission antenna2001_1 to the reception antenna 2002_1 is represented by h11(i), apropagation coefficient from the transmission antenna 2001_1 to thereception antenna 2002_2 is represented by h21(i), a propagationcoefficient from the transmission antenna 2001_2 to the receptionantenna 2002_1 is represented by h12(i), and a propagation coefficientfrom the transmission antenna 2001_2 to the reception antenna 2002_2 isrepresented by h22(i). Accordingly, the following Expression (41) as arelational expression holds.

$\begin{matrix}{\begin{pmatrix}{r1(i)} \\{r2(i)}\end{pmatrix} = {{\begin{pmatrix}{h11(i)} & {h12(i)} \\{h21(i)} & {{h22}(i)}\end{pmatrix}\begin{pmatrix}{u1(i)} \\{u2(i)}\end{pmatrix}} + \begin{pmatrix}{n1(i)} \\{n2(i)}\end{pmatrix}}} & {{Expression}(41)}\end{matrix}$

Here, n1(i) and n2(i) represent noise.

The modulated signal u1 channel estimator 1905_1 in FIG. 19 receives thebaseband signal 1904X, performs channel estimation of the modulatedsignal u1, that is, estimates h11(i) in Expression (41), by using thepreamble and/or the pilot symbols in FIGS. 8 and 9 (or FIGS. 10 and 11), and outputs a channel estimation signal 1906_1.

The modulated signal u2 channel estimator 1905_2 receives the basebandsignal 1904X, performs channel estimation of the modulated signal u2,that is, estimates h12(i) in Expression (41), by using the preambleand/or the pilot symbols in FIGS. 8 and 9 (or FIGS. 10 and 11 ), andoutputs a channel estimation signal 1906_2.

The modulated signal u1 channel estimator 1907_1 receives the basebandsignal 1904Y, performs channel estimation of the modulated signal u1,that is, estimates h21(i) in Expression (41), by using the preambleand/or the pilot symbols in FIGS. 8 and 9 (or FIGS. 10 and 11 ), andoutputs a channel estimation signal 1908_1.

The modulated signal u2 channel estimator 1907_2 receives the basebandsignal 1904Y, performs channel estimation of the modulated signal u2,that is, estimates h22(i) in Expression (41), by using the preambleand/or the pilot symbols in FIGS. 8 and 9 (or FIGS. 10 and 11 ), andoutputs a channel estimation signal 1908_2.

A control information decoder 1909 receives the baseband signals 1904Xand 1904Y, demodulates and decodes the control information in FIGS. 8and 9 (or FIGS. 10 and 11 ), and outputs the control signal 1910including the control information.

A signal processor 1911 receives the channel estimation signals 1906_1,1906_2, 1908_1, and 1908_2, the baseband signals 1904X and 1904Y, andthe control signal 1910. The signal processor 1911 performs demodulationand decoding by using the relationship in Expression (41) on the basisof the control information in the control signal 1910 (for example,information about a modulation scheme and a scheme related toerror-correcting code), and outputs reception data 1912.

The control signal 1910 need not necessarily be a signal generated byusing the method illustrated in FIG. 19 . For example, the controlsignal 1910 in FIG. 19 may be a signal generated on the basis ofinformation transmitted by the transmission apparatus (FIG. 1 ) as acommunication partner of FIG. 19 . Alternatively, the receptionapparatus in FIG. 19 may include an input section, and the controlsignal 1910 may be generated on the basis of information input from theinput section.

Example of Configuration of Antenna Section

Next, a description will be given of the configuration of the antennasection in which the control signal 1910 exists as input. FIG. 21 is adiagram illustrating an example of the configuration of the antennasection in FIG. 19 (the antenna section #X (1901X) or the antennasection #Y (1901Y)). The example in FIG. 19 is an example in which theantenna section is constituted by four antennas 2101_1 to 2101_4.

A multiplier 2103_1 receives a reception signal 2102_1 received by theantenna 2101_1 and a control signal 2100. On the basis of informationabout a multiplication coefficient included in the control signal 2100,the multiplier 2103_1 multiplies the reception signal 2102_1 by themultiplication coefficient, and outputs a multiplied signal 2104_1.

When the reception signal 2102_1 is represented by Rx1(t) (t is time)and the multiplication coefficient is represented by D1 (D1 can bedefined as a complex number and thus may be a real number), themultiplied signal 2104_1 is expressed by Rx1(t)×D1.

A multiplier 2103_2 receives a reception signal 2102_2 received by theantenna 2101_2 and the control signal 2100. On the basis of informationabout a multiplication coefficient included in the control signal 2100,the multiplier 2103_2 multiplies the reception signal 2102_2 by themultiplication coefficient, and outputs a multiplied signal 2104_2.

When the reception signal 2102_2 is represented by Rx2(t) and themultiplication coefficient is represented by D2 (D2 can be defined as acomplex number and thus may be a real number), the multiplied signal2104_2 is expressed by Rx2(t)×D2.

A multiplier 2103_3 receives a reception signal 2102_3 received by theantenna 2101_3 and the control signal 2100. On the basis of informationabout a multiplication coefficient included in the control signal 2100,the multiplier 2103_3 multiplies the reception signal 2102_3 by themultiplication coefficient, and outputs a multiplied signal 2104_3.

When the reception signal 2102_3 is represented by Rx3(t) and themultiplication coefficient is represented by D3 (D3 can be defined as acomplex number and thus may be a real number), the multiplied signal2104_3 is expressed by Rx3(t)×D3.

A multiplier 2103_4 receives a reception signal 2102_4 received by theantenna 2101_4 and the control signal 2100. On the basis of informationabout a multiplication coefficient included in the control signal 2100,the multiplier 2103_4 multiplies the reception signal 2102_4 by themultiplication coefficient, and outputs a multiplied signal 2104_4.

When the reception signal 2102_4 is represented by Rx4(t) and themultiplication coefficient is represented by D4 (D4 can be defined as acomplex number and thus may be a real number), the multiplied signal2104_4 is expressed by Rx4(t)×D4.

A combiner 2105 receives the multiplied signals 2104_1, 2104_2, 2104_3,and 2104_4. The combiner 2105 combines the multiplied signals 2104_1,2104_2, 2104_3, and 2104_4, and outputs a combined signal 2106. Thecombined signal 2106 is expressed byRx1(t)×D1+Rx2(t)×D2+Rx3(t)×D3+Rx4(t)×D4.

In FIG. 21 , a description is given of an example in which the antennasection is constituted by four antennas (and four multipliers), but thenumber of antennas is not limited to four, and is it sufficient that theantenna section be constituted by two or more antennas.

In a case where the antenna section #X (1901X) in FIG. 19 has theconfiguration in FIG. 21 , the reception signal 1902X corresponds to thecombined signal 2106 in FIG. 21 and the control signal 1910 correspondsto the control signal 2100 in FIG. 21 . In a case where the antennasection #Y (1901Y) in FIG. 19 has the configuration in FIG. 21 , thereception signal 1902Y corresponds to the combined signal 2106 in FIG.21 and the control signal 1910 corresponds to the control signal 2100 inFIG. 21 .

However, the antenna section #X (1901X) and the antenna section #Y(1901Y) need not necessarily have the configuration as in FIG. 21 , andthe antenna section need not necessarily receive the control signal1910, as described above. The antenna section #X (1901X) and the antennasection #Y (1901Y) each may be one antenna.

The control signal 1910 may be generated on the basis of informationtransmitted by the transmission apparatus as a communication partner.Alternatively, the reception apparatus may include an input section, andthe control signal 1910 may be generated on the basis of informationinput from the input section.

As described above, in the present embodiment, the transmissionapparatus in FIG. 1 is able to transmit modulated signals (basebandsignals) for multiple users at identical times and identical frequencies(bands) by using multiple antennas. Accordingly, the data transmissionefficiently of the transmission apparatus in FIG. 1 can be increased.The transmission apparatus in FIG. 1 sets, for each user, whether totransmit multiple streams or a single stream (or not to transmit amodulated signal), and also sets, for each user, a modulation scheme (aset of modulation schemes in a case where there are multiple mappers)and an error-correcting coding scheme, thereby being able to preferablycontrol the data transmission efficiency.

When the transmission apparatus in FIG. 1 transmits multiple modulatedsignals (baseband signals) to users, performing phase change increases apossibility of being able to avoid falling into a steadily poorreception state in an environment in which direct waves are dominant.Accordingly, the data reception quality at the reception apparatus as acommunication partner can be improved.

Second Embodiment

In the present embodiment, a description will be given of an example ofa communication apparatus including the transmission apparatus in FIG. 1described in the first embodiment, a communication apparatus includingthe reception apparatus in FIG. 19 described in the first embodiment,and a flow of communication between the communication apparatuses.

For the description given below, the communication apparatus includingthe transmission apparatus in FIG. 1 is called a “base station (accesspoint (AP))”, and the communication apparatus including the receptionapparatus in FIG. 19 is called a “terminal”.

Thus, the user #1 signal processor 102_1 in FIG. 1 is a signal processorfor generating a modulated signal for transmitting data to a terminal#1, the user #2 signal processor 102_2 is a signal processor forgenerating a modulated signal for transmitting data to a terminal #2,and the user #M signal processor 102_M is a signal processor forgenerating a modulated signal for transmitting data to a terminal #M.

FIG. 22 is a diagram illustrating an example of the configuration of thebase station (AP) including the transmission apparatus in FIG. 1 . InFIG. 22 , the elements similar to those in FIG. 1 are denoted by thesame numerals, and the description thereof is omitted.

A radio section group 153 receives a reception signal group 152 receivedby a reception antenna group 151. The radio section group 153 performsprocessing such as frequency conversion on the reception signal group152, and outputs a baseband signal group 154 to a signal processor 155.

The signal processor 155 performs processing such as demodulation anderror-correcting decoding on the baseband signal group input thereto,and outputs reception data 156 and control information 157. At thistime, the control information 157 includes feedback informationtransmitted by each terminal.

A setter 158 receives base station (AP) setting information 159 and thecontrol information 157. The setter 158 performs “deciding of anerror-correcting coding method, a transmission method, a modulationscheme (or a modulation scheme set), and so forth in the user #1 signalprocessor 102_1 in FIG. 1 ”, “deciding of an error-correcting codingmethod, a transmission method, a modulation scheme (or a modulationscheme set), and so forth in the user #2 signal processor 102_2 in FIG.1 ”, and “deciding of an error-correcting coding method, a transmissionmethod, a modulation scheme (or a modulation scheme set), and so forthin the user #M signal processor 102_M in FIG. 1 ”, and outputs a signalincluding the decided information as the control signal 100.

In addition, on the basis of the feedback information included in thecontrol information 157 and transmitted by each terminal, the setter 158decides the processing method to be used by the multiplexing signalprocessor 104, and outputs a signal including information about thedecided processing method as the control signal 100.

In FIG. 22 , the term “group” is used, but it is sufficient that areceiving section have one or more systems.

FIG. 23 is a diagram illustrating an example of the configuration of theterminal including the reception apparatus in FIG. 19 . In FIG. 23 , theelements that operate similarly to those in FIG. 19 are denoted by thesame numerals.

The signal processor 1911 receives the channel estimation signal 1906_1,the channel estimation signal 1906_2, the baseband signal 1904X, thechannel estimation signal 1908_1, the channel estimation signal 1908_2,the baseband signal 1904Y, and the control signal 1910. The signalprocessor 1911 performs processing of demodulation and error-correctingdecoding, and outputs the reception data 1912. In addition, the signalprocessor 1911 generates feedback information about the state of thereception signal on the basis of the signal transmitted by the basestation (AP), and outputs feedback information 1999.

A transmission signal processor 1952 receives data 1951 and the feedbackinformation 1999. The transmission signal processor 1952 performsprocessing such as error-correcting coding and modulation on the data1951 and the feedback information 1999 to generate a baseband signalgroup 1953, and outputs the baseband signal group 1953 to a radiosection group 1954.

The radio section group 1954 performs processing such as frequencyconversion and amplification on the baseband signal group 1953 inputthereto to generate a transmission signal group 1955. The radio sectiongroup 1954 outputs the transmission signal group 1955 to a transmissionantenna group 1956. Subsequently, the transmission signal group 1955 isoutput as radio waves from the transmission antenna group 1956.

In FIG. 23 , the term “group” is used, but it is sufficient that atransmitting section have one or more systems.

The base station (AP) transmits a signal to a terminal by using theconfiguration of the transmission apparatus in FIG. 1 and receives asignal from the terminal by using the configuration in FIG. 22 . Theterminal receives a signal from the base station (AP) by using theconfiguration of the reception apparatus in FIG. 19 and transmits asignal to the base station by using the configuration in FIG. 23 . Withthese configurations, communication is performed between the basestation (AP) and the terminal.

Next, a description will be given of a flow of communication between abase station (AP) and terminals.

FIG. 24 is a diagram illustrating an example of the relationship betweena base station (AP) and terminals. In a base station (AP) 2400, the user#1 signal processor 102_1 in FIG. 1 generates a modulated signal to betransmitted to a terminal #1 (2401_1), for example, the user #1 signalprocessor 102_2 in FIG. 1 generates a modulated signal to be transmittedto a terminal #2 (2401_2), for example, and the user #M signal processor102_M in FIG. 1 generates a modulated signal to be transmitted to aterminal #M (2401_M), for example.

The base station (AP) 2400 generates a transmission directivity 2411_1,and the terminal #1 (2401_1) generates a reception directivity 2421_1.With use of the transmission directivity 2411_1 and the receptiondirectivity 2421_1, the transmission signal for the terminal #1transmitted by the base station (AP) 2400 is received by the terminal #1(2401_1).

Also, the base station (AP) 2400 generates a transmission directivity2411_2, and the terminal #2 (2401_2) generates a reception directivity2421_2. With use of the transmission directivity 2411_2 and thereception directivity 2421_2, the transmission signal for the terminal#2 transmitted by the base station (AP) 2400 is received by the terminal#2 (2401_2).

The base station (AP) 2400 generates a transmission directivity 2411_M,and the terminal #M (2401_M) generates a reception directivity 2421_M.With use of the transmission directivity 2411_M and the receptiondirectivity 2421_M, the transmission signal for the terminal #Mtransmitted by the base station (AP) 2400 is received by the terminal #M(2401_M).

In the example in FIG. 24 , it is assumed that the base station (AP)2400 transmits the modulated signal to the terminal #1, the modulatedsignal to the terminal #2, and the modulated signal to the terminal #Mby using identical times and identical frequencies (bands). This pointhas been described in the first embodiment. FIG. 24 illustrates“transmits the modulated signal to the terminal #1, the modulated signalto the terminal #2, and the modulated signal to the terminal #M by usingidentical times and identical frequencies (bands)”, but this is merelyan example. The number of modulated signals transmitted by the basestation (AP) 2400 by using identical times and identical frequencies(bands) is not limited to this example. In addition, there may be a timeat which modulated signals are not multiplexed.

FIG. 25 is a diagram illustrating an example of a temporal flow ofcommunication between the base station (AP) and the terminals. FIG. 25illustrates transmission signals of the base station (AP), transmissionsignals of the terminal #1, transmission signals of the terminal #2, andtransmission signals of the terminal #M. The horizontal axis in FIG. 25indicates time. A terminal other than the terminal #1, the terminal #2,and the terminal #M may transmit transmission signals.

As illustrated in FIG. 25 , it is assumed that the terminal #1 issues anaccess request (transmission of data by the base station (AP)) 2501_1 tothe base station (AP). Likewise, it is assumed that the terminal #2issues an access request (transmission of data by the base station (AP))2501_2 to the base station (AP). It is assumed that the terminal #Missues an access request (transmission of data by the base station (AP))2501_M to the base station (AP).

It is assumed that the base station (AP) transmits a reference symbol(2502) in response to the access requests. For example, a PSK symbolthat is known to the terminals is transmitted as the reference symbol2502. However, the configuration of the reference symbol 2502 is notlimited thereto. The reference symbol 2502 corresponds to the (common)reference signal 199 illustrated in FIG. 1 .

Accordingly, the terminal #1 receives the reference symbol 2502transmitted by the base station. Subsequently, for example, the terminal#1 estimates the reception state at each reception antenna of theterminal #1 and transmits information about the reception state at eachreception antenna as feedback information 2503_1. Likewise, the terminal#2 receives the reference symbol 2502 transmitted by the base station.Subsequently, for example, the terminal #2 estimates the reception stateat each reception antenna of the terminal #2 and transmits informationabout the reception state at each reception antenna as feedbackinformation 2503_2. Likewise, the terminal #M receives the referencesymbol 2502 transmitted by the base station. For example, the terminal#M estimates the reception state at each reception antenna of theterminal #M and transmits information about the reception state at eachreception antenna as feedback information 2503_M.

The base station (AP) receives the pieces of feedback informationtransmitted by the individual terminals. For example, in FIG. 22 , it isassumed that the control information 157 includes the pieces of feedbackinformation transmitted by the individual terminals. The setter 158 inFIG. 22 receives the control information 157 including the pieces offeedback information transmitted by the individual terminals, decidesthe processing method to be performed by the multiplexing signalprocessor 104 in FIG. 1 , and outputs the control signal 100 includingthis information.

Subsequently, the base station (AP) transmits each data symbol to eachterminal (2504), for example, as illustrated in FIG. 25 . Regarding“transmit each data symbol and so forth” 2504 illustrated in FIG. 25 ,symbols other than data symbols may exist, such as pilot symbols,control information symbols, reference symbols, and a preamble. The basestation (AP) transmits modulated signals for individual terminals byusing identical times and identical frequencies (bands). The details ofthis point have been described in the first embodiment.

Third Embodiment

In the first embodiment, a description has been given mainly of anexample in which, when the transmission apparatus in FIG. 1 generatesmultiple modulated signals to be transmitted to the user #p, the phasechanger 305B (see FIGS. 3 and 4 ) performs phase change on at least onemodulated signal that has been subjected to precoding. In a thirdembodiment, a description will be given of processing in which thetransmission apparatus in FIG. 1 switches, in accordance with thecontrol signal 300, between “perform phase change and not perform phasechange” in the phase changer 305B. Also, in the third embodiment, adescription will be given of processing in which, when the transmissionapparatus in FIG. 1 transmits a signal, the transmission scheme of thesignal is changed on the basis of information received from acommunication partner.

Hereinafter, a description will be given of a case where the basestation (AP) including the transmission apparatus in FIG. 1 iscommunicating with terminals.

At this time, it is assumed that the base station (AP) is able totransmit multiple modulated signals including multiple streams of datato individual users (individual terminals) by using multiple antennas.

For example, it is assumed that the base station (AP) includes thetransmission apparatus in FIG. 1 to transmit multiple modulated signalsincluding multiple streams of data to the user #p (p is an integer from1 to M) by using multiple antennas.

In FIG. 1 , it is assumed that, when generating multiple modulatedsignals to be transmitted to the user #p, phase change is performed onat least one modulated signal that has been subjected to precoding. Theoperation for performing phase change has been described in the firstembodiment, and thus the description thereof is omitted.

Here, it is assumed that the base station (AP) is able to switch between“perform phase change and not perform phase change” in accordance with acontrol signal when generating multiple modulated signals includingmultiple streams of data for the user #p. Specifically, it is assumedthat it is possible to switch between “perform phase change and notperform phase change” in the phase changer 305B in FIG. 3 in accordancewith the control signal 300. The operation for performing phase changehas been described in the first embodiment. In the case of notperforming phase change, the phase changer 305B outputs the signal 304Bas 306B.

Thus, the following operations are performed in the case of performingphase change and in the case of not performing phase change.

Case of Performing Phase Change

The base station (AP) performs phase change on at least one modulatedsignal, and then transmits multiple modulated signals by using multipleantennas.

The method for performing phase change on at least one modulated signaland transmitting multiple modulated signals by using multiple antennashas been described in the first embodiment, for example.

Case of Not Performing Phase Change

The base station (AP) performs precoding (weight combining) on modulatedsignals (baseband signals) of multiple streams and transmits thegenerated multiple modulated signals by using multiple antennas.However, the precoder (weight combiner) need not necessarily performprecoding.

The base station (AP) transmits control information for notifying theterminal as a communication partner of the setting of performing or notperforming phase change by using a preamble, for example.

As described above, “phase change is performed on at least one modulatedsignal”. Specifically, a description has been given, with reference toFIG. 3 , that phase change is performed on one modulated signal amongmultiple modulated signals. Now, a description will be given of the caseof “performing phase change on multiple modulated signals” withreference to FIG. 26 , instead of FIG. 3 .

FIG. 26 is a diagram illustrating an example of the configuration of thesignal processor 206 in FIG. 2 , different from the example in FIG. 3 .In FIG. 26 , a point different from FIG. 3 will be described.

A phase changer 305A receives the control signal 300. On the basis ofthe control signal 300, the phase changer 305A determines whether or notto perform phase change. In a case where the phase changer 305Adetermines to perform phase change, the phase changer 305A performsphase change on the user #p weighted signal 304A (zp1′(t)) and outputs aphase-changed signal 306A. In a case where the phase changer 305Adetermines not to perform phase change, the phase changer 305A outputsthe signal 306A without performing phase change on the user #p weightedsignal 304A (zp1′(t)).

In FIG. 26 , zp1(i) and zp2(i) are based on Expression (3) as in thefirst embodiment. In a case where phase change is performed on zp1(i)and zp2(i) in FIG. 26 , it can be expressed by the following Expression(42).

$\begin{matrix}\begin{matrix}{\begin{pmatrix}{{zp}1(i)} \\{{zp}2(i)}\end{pmatrix} = {\begin{pmatrix}{Y{p(i)}} & 0 \\0 & {y{p(i)}}\end{pmatrix}\begin{pmatrix}a & b \\c & d\end{pmatrix}\begin{pmatrix}{{sp}1(i)} \\{{sp}2(i)}\end{pmatrix}}} \\{= {\begin{pmatrix}e^{j \times \lambda{p(i)}} & 0 \\0 & e^{j \times \delta{p(i)}}\end{pmatrix}\begin{pmatrix}a & b \\c & d\end{pmatrix}\begin{pmatrix}{{sp}1(i)} \\{{sp}2(i)}\end{pmatrix}}}\end{matrix} & {{Expression}(42)}\end{matrix}$

Here, λp(i) is a real number. Also, zp1(i) and zp2(i) are transmittedfrom the transmission apparatus at identical times and identicalfrequencies (identical frequency bands). The phase change in the phasechanger 305A may be performed by using, for example, a method forchanging the phase periodically or regularly.

In other embodiments such as the first embodiment and the secondembodiment, each embodiment can be carried out even by using FIG. 26instead of FIG. 3 as the configuration of the signal processor 206 inFIG. 2 .

Next, a description will be given of communication between the basestation (AP) and the terminal #p and processing based on data that istransmitted and received in the communication.

FIG. 27 is a diagram illustrating an example of communication betweenthe base station (AP) and the terminal #p. FIG. 27 illustrates a stateover time of a transmission signal from the base station (AP) and astate over time of a transmission signal from the terminal #p. In FIG.27 , the horizontal axis indicates time.

First, the base station (AP) transmits a transmission request 2701indicating “request information for transmitting a modulated signal” tothe terminal #p.

Subsequently, the terminal #p receives the transmission request 2701transmitted by the base station (AP) and transmits a receptioncapability notification symbol 2702 indicating the reception capabilityof the terminal to the base station (AP).

The base station (AP) receives the reception capability notificationsymbol 2702 transmitted by the terminal #p, and decides anerror-correcting coding method, a modulation scheme (or a set ofmodulation schemes), and a transmission method on the basis of theinformation of the reception capability notification symbol 2702. On thebasis of these methods that have been decided, the base station (AP)performs error-correcting coding, mapping in the modulation scheme, andother signal processing (for example, precoding, phase change, and soforth) on the information (data) to be transmitted, and transmits amodulated signal 2703 including data symbols and so forth to theterminal #p.

The data symbols and so forth 2703 may include, for example, controlinformation symbols. At this time, when transmitting data symbols byusing “a transmission method for transmitting multiple modulated signalsincluding multiple streams of data by using multiple antennas”, acontrol symbol including information for notifying the communicationpartner whether phase change has been performed on at least onemodulated signal or the foregoing phase change has not been performedmay preferably be transmitted. Accordingly, the communication partner isable to easily change the demodulation method.

The terminal #p receives the data symbols and so forth 2703 transmittedby the base station and obtains data.

The communication between the base station (AP) and the terminal in FIG.27 is performed by one or more terminals among the terminal #1 to theterminal #M and the base station (AP). The data symbols (including othersymbols) transmitted to each terminal are transmitted by the basestation by using identical times and identical frequencies (bands). Thispoint has been described in the first embodiment, the second embodiment,and so forth.

FIG. 28 is a diagram illustrating an example of data included in thereception capability notification symbol 2702 transmitted by theterminal #p in FIG. 27 . The data included in the reception capabilitynotification symbol 2702 is, for example, data indicating the receptioncapability of the terminal #p. The terminal #p transmits the dataindicating the reception capability to the base station (AP), andthereby the base station (AP) is able to transmit a transmission signalcorresponding to the reception capability to the terminal #p.

In FIG. 28, 2801 denotes data about “support/not support demodulation ofmodulated signal with phase change”, and 2802 denotes data about“support/not support reception directivity control”.

In the data 2801 about “support/not support demodulation of modulatedsignal with phase”, “support demodulation of modulated signal with phasechange” means the following.

“Support Demodulation of Modulated Signal with Phase Change”:

This means that, in a case where the base station (AP) performs phasechange on at least one modulated signal and transmits multiple modulatedsignals (multiple modulated signals including multiple streams) by usingmultiple antennas, the terminal #p is able to receive and demodulate themodulated signals. That is, this means that the terminal #p is able toperform demodulation in consideration of phase change and to obtaindata. The transmission method for performing phase change on at leastone modulated signal and transmitting multiple modulated signals byusing multiple antennas has already been described in an embodiment.

In the data 2801 about “support/not support demodulation of modulatedsignal with phase change”, “not support demodulation of modulated signalwith phase change” means the following.

“Not Support Demodulation of Modulated Signal with Phase Change”:

This means that, in a case where the base station (AP) performs phasechange on at least one modulated signal and transmits multiple modulatedsignals (multiple modulated signals including multiple streams) by usingmultiple antennas, the terminal #p is able to receive the modulatedsignals but is unable to demodulate the modulated signals. That is, thismeans that the terminal #p is unable to perform demodulation inconsideration of phase change. The transmission method for performingphase change on at least one modulated signal and transmitting multiplemodulated signals by using multiple antennas has already been describedin an embodiment.

For example, it is assumed that the data 2801 about “support/not supportdemodulation of modulated signal with phase change” (hereinafterreferred to as “data 2801”) is expressed by 1-bit data. Also, it isassumed that, in a case where the terminal #p “supports phase change” asdescribed above, the terminal #p transmits the data 2801 as “0”. Also,it is assumed that, in a case where the terminal #p “does not supportphase change” as described above, the terminal #p transmits the data2801 as “1”. The base station (AP) receives the data 2801 transmitted bythe terminal #p.

In a case where the data 2801 indicates “support phase change” (i.e.,the data 2801 is “0”) and the base station (AP) decides to transmitmodulated signals of multiple streams to the terminal #p by usingmultiple antennas (for example, in the case of deciding to generatemultiple modulated signals for transmitting multiple streams in the user#p signal processor 102_p illustrated in FIG. 1 ), the base station (AP)may generate modulated signals addressed to the user #p by using eitherof Method #1 and Method #2 described below and transmit the modulatedsignals. Alternatively, the base station (AP) generates modulatedsignals addressed to the user #p by using Method #2 described below andtransmits the modulated signals.

Method #1

The base station (AP) performs precoding (weight combining) on modulatedsignals (baseband signals) of multiple streams to be transmitted to theterminal #p and transmits the generated multiple modulated signals byusing multiple antennas. At this time, phase change is not performed.However, the precoder (weight combiner) need not necessarily performprecoding, as described above.

Method #2

The base station (AP) performs phase change on at least one modulatedsignal among multiple modulated signals to be transmitted to theterminal #p. Subsequently, the base station (AP) transmits the multiplemodulated signals to the terminal #p by using multiple antennas.

Here, it is important that the transmission methods selectable by thebase station (AP) include Method #2. Thus, the base station (AP) maytransmit the modulated signals by using a method other than Method #1and Method #2.

On the other hand, in a case where the data 2801 indicates “not supportphase change” (i.e., the data 2801 is “1”) and the base station (AP)decides to transmit modulated signals of multiple streams to theterminal #p by using multiple antennas, the base station (AP) transmitsthe modulated signals to the terminal #p by using Method #1, forexample.

Here, it is important that, when the base station (AP) transmits themodulated signals to the terminal #p, the transmission methodsselectable by the base station (AP) do not include Method #2. Thus, thebase station (AP) may transmit the modulated signals to the terminal #pby using a method that is different from Method #1 and that is notMethod #2.

The reception capability notification symbol 2702 may includeinformation other than the data 2801. For example, the receptioncapability notification symbol 2702 may include the data 2802 about“support/not support reception directivity control” indicating whetheror not the reception apparatus of the terminal supports receptiondirectivity control (hereinafter referred to as “data 2802”). Thus, theconfiguration of the reception capability notification symbol 2702 isnot limited to that in FIG. 28 .

For example, in a case where the terminal #p is able to performreception directivity control, the data 2802 is set to “0”. In a casewhere the terminal #p is unable to perform reception directivitycontrol, the data 2802 is set to “1”.

The terminal #p transmits the reception capability notification symbol2702 including the data 2802, and the base station (AP) determines, onthe basis of the reception capability notification symbol 2702, whetheror not the terminal #p is able to perform reception directivity control.If the base station (AP) determines that the terminal #p “supportsreception directivity control”, the base station (AP) and the terminal#p may transmit training symbols, reference symbols, control informationsymbols, and so forth for reception directivity control of the terminal#p.

FIG. 29 is a diagram illustrating an example of data included in thereception capability notification symbol 2702 transmitted by theterminal #p in FIG. 27 , different from the example in FIG. 28 . Thedata 2801 is the same as that in FIG. 28 .

Hereinafter, a description will be given of data 2901 about “support/notsupport reception for multiple streams” in FIG. 29 .

In the data 2901 about “support/not support reception for multiplestreams”, “support reception for multiple streams” means the following.

“Support Reception for Multiple Streams”:

This means that, in a case where the base station (AP) transmitsmultiple modulated signals addressed to the terminal #p from multipleantennas to transmit multiple streams to the terminal #p, the terminal#p is able to receive and demodulate the multiple modulated signalsaddressed to the terminal #p and transmitted by the base station.

However, for example, in a case where the base station (AP) transmitsmultiple modulated signals addressed to the terminal #p from themultiple antennas, it is not concerned about whether or not phase changehas been performed. That is, in a case where multiple transmissionmethods are defined as a transmission method in which the base station(AP) transmits multiple modulated signals addressed to the terminal #pby using multiple antennas to transmit multiple streams to the terminal#p, it is sufficient that there be at least one transmission method thatallows the terminal #p to demodulate the modulated signals.

In the data 2901 about “support/not support reception for multiplestreams”, “not support reception for multiple streams” means thefollowing.

“Not Support Reception for Multiple Streams”:

In a case where multiple transmission methods are defined as atransmission method in which the base station transmits multiplemodulated signals addressed to the terminal #p by using multipleantennas to transmit multiple streams to the terminal #p, the terminalis unable to demodulate the modulated signals even if the base stationtransmits the modulated signals by using any transmission method.

For example, it is assumed that the data 2901 about “support/not supportreception for multiple streams” (hereinafter referred to as “data 2901”)is expressed by 1-bit data. In a case where the terminal #p “supportsreception for multiple streams”, the terminal #p sets “0” as the data2901. In a case where the terminal #p “does not support reception formultiple streams”, the terminal #p sets “1” as the data 2901.

The base station (AP) performs phase change on at least one modulatedsignal among multiple modulated signals (multiple modulated signalsincluding multiple streams). Thus, in a case where the terminal #p doesnot support reception for multiple streams, the base station (AP) isunable to transmit multiple modulated signals, and eventually is unableto perform phase change.

Thus, in a case where the terminal #p sets “0” as the data 2901, thedata 2801 is valid. At this time, the base station (AP) decides, on thebasis of the data 2801 and the data 2901, a transmission method fortransmitting data.

In a case where the terminal #p sets “1” as the data 2901, the data 2801is invalid. At this time, the base station (AP) decides, on the basis ofthe data 2901, a transmission method for transmitting data.

In the above-described manner, the terminal transmits the receptioncapability notification symbol 2702, and the base station (AP) decides,on the basis of the symbol, a transmission method for transmitting data.Accordingly, it is possible to reduce cases where data is transmitted bya transmission method that does not allow the terminal #p to performdemodulation, which is advantageous in that data can be appropriatelytransmitted to the terminal #p. Thus, the data transmission efficiencyof the base station (AP) can be increased.

In addition, there is the data 2801 about “support/not supportdemodulation of modulated signal with phase change” as the receptioncapability notification symbol 2702. Thus, in a case where the terminal#p that supports phase change demodulation communicates with the basestation (AP), the base station (AP) is able to appropriately select amode in which “modulated signals are transmitted by using a transmissionmethod that performs phase change”. Accordingly, the terminal #p is ableto obtain data of high reception quality even in an environment in whichdirect waves are dominant. In addition, in a case where the terminal #pthat does not support phase change demodulation communicates with thebase station (AP), the base station (AP) is able to appropriately selecta transmission method that allows the terminal to perform reception.Accordingly, the data transmission efficiency can be increased.

FIG. 27 illustrates the transmission signal from the base station (AP)and the transmission signal from the terminal #p, but the transmissionsignals are not limited thereto. For example, the signal illustrated asthe transmission signal from the base station (AP) in FIG. 27 may be thetransmission signal from the terminal, and the signal illustrated as thetransmission signal from the terminal #p in FIG. 27 may be thetransmission signal from the base station (AP).

Alternatively, the signal illustrated as the transmission signal fromthe base station (AP) in FIG. 27 may be a transmission signal from aterminal other than the terminal #p. That is, the transmission andreception of the signals illustrated in FIG. 27 may be transmission andreception between terminals.

Alternatively, the transmission and reception of the signals illustratedin FIG. 27 may be transmission and reception between base stations(APs).

The transmission and reception is not limited to these examples, and anycommunication between communication apparatuses may be performed.

The data symbols in the data symbols and so forth 2703 in FIG. 27 may bea signal of a multi-carrier scheme such as OFDM or may be a signal of asingle-carrier scheme. Likewise, the reception capability notificationsymbol 2702 in FIG. 27 may be a signal of a multi-carrier scheme such asOFDM or may be a signal of a single-carrier scheme.

For example, in a case where the reception capability notificationsymbol 2702 in FIG. 27 is of a single-carrier scheme, the terminal isable to reduce power consumption in the case of FIG. 27 .

In the description given above, when the base station (AP) iscommunicating with multiple terminals, the base station (AP) receivesreception capability notification symbols (see 2702) from the multipleterminals. At this time, each terminal transmits, as the “receptioncapability notification symbol”, the data illustrated in FIG. 28 or 29 ,for example, and the base station (AP) decides a transmission method formodulated signals for each terminal. When the base station (AP)transmits modulated signals to the multiple terminals, the base station(AP) transmits the modulated signals addresses to the individualterminals by using the methods described in the first embodiment and thesecond embodiment, for example.

Next, a description will be given of another example of the receptioncapability notification symbol 2702 with reference to FIG. 30 .

FIG. 30 is a diagram illustrating an example of data included in thereception capability notification symbol 2702 transmitted by theterminal #p in FIG. 27 , different from the examples in FIGS. 28 and 29. The data 2801 about “support/not support demodulation of modulatedsignal with phase change” is the same as those in FIGS. 28 and 29 .Also, the data 2901 about “support/not support reception for multiplestreams” is the same as that in FIG. 29 .

A description will be given of data 3001 about “supported schemes”(hereinafter referred to as “data 3001”) in FIG. 30 . It is assumed thatthe transmission of modulated signals to the terminals by the basestation (AP) and the transmission of modulated signals to the basestation (AP) by the terminals in FIG. 24 are the transmission ofmodulated signals in a communication scheme in a specific frequency(band). Also, it is assumed that a communication scheme #A and acommunication scheme #B exist as examples of the “communication schemein a specific frequency (band)”.

It is assumed that “communication scheme #A” does not support a “schemefor transmitting multiple modulated signals including multiple streamsby using multiple antennas”. That is, there is no option of a “schemefor transmitting multiple modulated signals including multiple streamsby using multiple antennas” as “communication scheme #A”. In addition,it is assumed that “communication scheme #B” supports a “scheme fortransmitting multiple modulated signals including multiple streams byusing multiple antennas”. That is, the “scheme for transmitting multiplemodulated signals including multiple streams by using multiple antennas”is selectable as “communication scheme #B”.

For example, it is assumed that the data 3001 is made up of 2 bits.Also, it is assumed that the 2-bit data is set as follows.

In a case where the terminal #p supports only “communication scheme #A”,the data 3001 is set to “01”. In a case where the data 3001 is set to“01”, even if the base station (AP) transmits a modulated signal of“communication scheme #B”, the terminal #p is unable to demodulate themodulated signal and obtain data.

In a case where the terminal #p supports only “communication scheme #B”,the data 3001 is set to “10”. In a case where the data 3001 is set to“10”, even if the base station (AP) transmits a modulated signal of“communication scheme #A”, the terminal #p is unable to demodulate themodulated signal and obtain data.

In a case where the terminal #p supports both “communication scheme #A”and “communication scheme #B”, the data 3001 is set to “11”.

Next, a description will be given of data 3002 about “support/notsupport multi-carrier scheme” (hereinafter referred to as data 3002) inFIG. 30 . It is assumed that “communication scheme #A” is able to selecta “single-carrier scheme” or a “multi-carrier scheme such as the OFDMscheme” as a transmission method for modulated signals. Also, it isassumed that “communication scheme #B” is able to select a“single-carrier scheme” or a “multi-carrier scheme such as the OFDMscheme” as a transmission method for modulated signals.

For example, it is assumed that the data 3002 is made up of 2 bits.Also, it is assumed that the 2-bit data is set as follows.

In a case where the terminal #p supports only “single-carrier scheme”,the data 3002 is set to “01”. In a case where the data 3002 is set to“01”, even if the base station (AP) transmits a modulated signal of“multi-carrier scheme such as the OFDM scheme”, the terminal #p isunable to demodulate the modulated signal and obtain data.

In a case where the terminal #p supports only “multi-carrier scheme suchas the OFDM scheme”, the data 3002 is set to “10”. In a case where thedata 3002 is set to “10”, even if the base station (AP) transmits amodulated signal of “single-carrier scheme “, the terminal #p is unableto demodulate the modulated signal and obtain data.

In a case where the terminal #p supports both “single-carrier scheme”and “multi-carrier scheme such as the OFDM scheme”, the data 3002 is setto “11”.

Next, a description will be given of data 3003 about “supportederror-correcting coding schemes” (hereinafter referred to as data 3003)in FIG. 30 . For example, it is assumed that “error-correcting codingscheme #C” is an “error-correcting coding method that supports one ormore coding rates with a code length (block length) of c bits (c is aninteger equal to or greater than 1)”. It is assumed that“error-correcting coding scheme #D” is an “error-correcting codingmethod that supports one or more coding rates with a code length (blocklength) of d bits (d is an integer equal to or greater than 1 and isgreater than c (d>c))”. As a method that supports one or more codingrates, an error-correcting code that varies according to a coding ratemay be used, or one or more coding rates may be supported by puncturing.In addition, one or more coding rates may be supported by both of them.

It is assumed that only “error-correcting coding scheme #C” isselectable in “communication scheme #A” and that “error-correctingcoding scheme #C” and “error-correcting coding scheme #D” are selectablein “communication scheme #B”.

For example, it is assumed that the data 3003 is made up of 2 bits.Also, it is assumed that the 2-bit data is set as follows.

In a case where the terminal #p supports only “error-correcting codingscheme #C”, the data 3003 is set to “01”. In a case where the data 3003is set to “01”, even if the base station (AP) generates and transmits amodulated signal by using “error-correcting coding scheme #D”, theterminal #p is unable to demodulate and decode the modulated signal andobtain data.

In a case where the terminal #p supports only “error-correcting codingscheme #D”, the data 3003 is set to “10”. In a case where the data 3003is set to “10”, even if the base station (AP) generates and transmits amodulated signal by using “error-correcting coding scheme #C”, theterminal #p is unable to demodulate and decode the modulated signal andobtain data.

In a case where the terminal #p supports both “error-correcting codingscheme #C” and “error-correcting coding scheme #D”, the data 3003 is setto “11”.

The base station (AP) receives the reception capability notificationsymbol 2702 that is transmitted by the terminal #p and that has theconfiguration illustrated in FIG. 30 , for example. Subsequently, thebase station (AP) decides a method for generating modulated signalsincluding data symbols addressed to the terminal #p on the basis of thecontent of the reception capability notification symbol 2702, andtransmits the modulated signals addressed to the terminal #p.

Characteristic points at this time will be described.

Example 1

In a case where the terminal #p transmits the data 3001 set to “01”(i.e., “communication scheme #A” is supported), the base station (AP)that has obtained the data determines that the data 3003 is invalidbecause “error-correcting coding scheme #D” is not selectable in“communication scheme #A”. When generating modulated signals addressedto the terminal #p, the base station (AP) performs error-correctingcoding by using “error-correcting coding scheme #C”.

Example 2

In a case where the terminal #p transmits the data 3001 set to “01”(i.e., “communication scheme #A” is supported), the base station (AP)that has obtained the data determines that the data 2801 and the data2901 are invalid because the “scheme for transmitting multiple modulatedsignals including multiple streams by using multiple antennas” is notsupported in “communication scheme #A”. When generating modulatedsignals addressed to the terminal, the base station (AP) generates amodulated signal of a single stream and transmits it.

In addition to the above, a case with the following constraints will bediscussed. Constraint condition 1: In “communication scheme #B”, it isassumed that, in the single-carrier scheme, in the “scheme fortransmitting multiple modulated signals including multiple streams byusing multiple antennas”, the scheme for “performing phase change on atleast one modulated signal among multiple modulated signals” is notsupported (other schemes may be supported), and that, in themulti-carrier scheme such as the OFDM scheme, at least the scheme for“performing phase change on at least one modulated signal among multiplemodulated signals” is supported (other schemes may be supported).

In this case, the following arises.

Example 3

In a case where the terminal #p transmits the data 3002 set to “01”(i.e., only the single-carrier scheme is supported), the base station(AP) that has obtained the data determines that the data 2801 isinvalid. When generating modulated signals addressed to the terminal #p,the base station (AP) does not use the scheme for “performing phasechange on at least one modulated signal among multiple modulatedsignals”.

FIG. 30 is an example of the reception capability notification symbol2702 transmitted by the terminal #p. As described above by using FIG. 30, in a case where the terminal #p transmits multiple pieces of receptioncapability information (for example, the data 2801, the data 2901, thedata 3001, the data 3002, and the data 3003 in FIG. 30 ), the basestation (AP) may need to determine that some of the multiple pieces ofreception capability information are invalid when deciding a method forgenerating modulated signals addressed to the terminal #p on the basisof the reception capability notification symbol 2702. In considerationof this, if the terminal #p bundles the multiple pieces of receptioncapability information and transmits it as the reception capabilitynotification symbol 2702, the base station (AP) is able to easily decidethe generation of the modulated signals addressed to the terminal #p ina short processing time.

The data structure descried in the third embodiment is merely an exampleand is not limited thereto. In addition, the number of bits of eachpiece of data and a bit setting method are not limited to the examplesdescribed in the third embodiment.

Fourth Embodiment

In the first embodiment, the second embodiment, and the thirdembodiment, a description has been given that either of the case ofgenerating multiple modulated signals including multiple streams and thecase of generating a modulated signal of a single stream is possible inthe user #p signal processor 102_p (p is an integer from 1 to M) in FIG.1 . In a fourth embodiment, a description will be given of anotherexample of the configuration of the user #p signal processor 102_p atthis time.

FIG. 31 is a diagram illustrating an example of the configuration of theuser #p signal processor 102_p. In FIG. 31 , the elements that operatesimilarly to those in FIG. 2 are denoted by the same numerals. In FIG.31 , the detailed operation of the signal processor 206 has beendescribed in the first embodiment and thus the description thereof isomitted. Hereinafter, characteristic operations will be described.

It is assumed that the control signal 200 includes informationindicating which of the “method for transmitting a modulated signal of asingle stream” and the “method for transmitting multiple modulatedsignals including multiple streams” is to be used in each user signalprocessor.

In a case where generation of modulated signals using the “method fortransmitting multiple modulated signals including multiple streams” isdesignated by the control signal 200 in the user #p signal processor102_p, the signal processor 206 generates multiple modulated signalsincluding multiple streams, outputs a user #p processed signal 206_A toa signal selector 3101, and outputs a user #p processed signal 206_B toan output controller 3102.

The signal selector 3101 receives the control signal 200, the user #pprocessed signal 206_A, and the mapped signal 205_1. Since thegeneration of modulated signals using the “method for transmittingmultiple modulated signals including multiple streams” is designated bythe control signal 200, the signal selector 3101 outputs the user #pprocessed signal 206_A as a selected signal 206_A′. The selected signal206_A′ corresponds to the user #p first baseband signal 103_p_1 in FIG.1 .

The output controller 3102 receives the control signal 200 and the user#p processed signal 206_B. Since the generation of modulated signalsusing the “method for transmitting multiple modulated signals includingmultiple streams” is designated by the control signal 200, the outputcontroller 3102 outputs the user #p processed signal 206_B as an outputsignal 206_B′. The output signal 206_B′ corresponds to the user #psecond baseband signal 103_p_2 in FIG. 1 .

In the user #p signal processor 102_p, in a case where the generation ofa modulated signal using the “method for transmitting a modulated signalof a single stream” is designated by the control signal 200, the signalprocessor 206 does not operate.

In addition, the mapper 204 does not output the mapped signal 205_2.

The signal selector 3101 receives the control signal 200, the user #pprocessed signal 206_A, and the mapped signal 205_1. Since thegeneration of a modulated signal using the “method for transmitting amodulated signal of a single stream” is designated by the control signal200, the signal selector 3101 outputs the mapped signal 205_1 as theselected signal 206_A′. The selected signal 206_A′ corresponds to theuser #p first baseband signal 103_p_1 in FIG. 1 .

The output controller 3102 receives the control signal 200 and the user#p processed signal 206_B. Since the generation of a modulated signalusing the “method for transmitting a modulated signal of a singlestream” is designated by the control signal 200, the output controller3102 does not output the output signal 206_B′.

With the above-described operation, in the user #p signal processor102_p in FIG. 1 , outputting of a modulated signal can be realized ineither of the case of generating multiple modulated signals includingmultiple streams and the case of generating a modulated signal of asingle stream.

A description has been given that either of the case of generatingmultiple modulated signals including multiple streams and the case ofgenerating a modulated signal of a single stream is possible in the user#p signal processor 102_p (p is an integer from 1 to M) in FIG. 1 . Now,with reference to FIG. 32 , a description will be given of an example ofthe configuration of the user #p signal processor 102_p different fromthe example in FIG. 31 .

FIG. 32 is a diagram illustrating an example of the configuration of theuser #p signal processor 102_p. The elements similar to those in FIGS. 2and 31 are denoted by the same numerals. In FIG. 32 , the detailedoperation of the signal processor 206 has been described in the firstembodiment, and thus the description thereof is omitted. Hereinafter,characteristic operations will be described.

It is assumed that the control signal 200 includes informationindicating whether the “scheme for transmitting a modulated signal of asingle stream” or the “scheme for transmitting multiple modulatedsignals including multiple streams” is to be used in each user signalprocessor.

In a case where the generation of modulated signals using the “methodfor transmitting multiple modulated signals including multiple streams”is designated by the control signal 200 in the user #p signal processor102_p, the signal processor 206 operates, generates multiple modulatedsignals including multiple streams, and outputs the user #p processedsignals 206_A and 206_B.

The signal selector 3101 receives the control signal 200, the user #pprocessed signal 206_A, and a processed signal 3202_1. Since thegeneration of modulated signals using the “method for transmittingmultiple modulated signals including multiple streams” is designated bythe control signal 200, the signal selector 3101 outputs the user #pprocessed signal 206_A as the selected signal 206_A′. The selectedsignal 206_A′ corresponds to the user #p first baseband signal 103_p_1in FIG. 1 .

A signal selector 3203 receives the control signal 200, the user #pprocessed signal 206_B, and a processed signal 3202_2. Since thegeneration of modulated signals using the “method for transmittingmultiple modulated signals including multiple streams” is designated bythe control signal 200, the signal selector 3203 outputs the user #pprocessed signal 206_B as the selected signal 206_B′. The selectedsignal 206_B′ corresponds to the user #p second baseband signal 103_p_2in FIG. 1 .

In the user #p signal processor 102_p, in a case where the generation ofa modulated signal using the “method for transmitting a modulated signalof a single stream” is designated by the control signal 200, the signalprocessor 206 does not operate.

In addition, the mapper 204 does not output the mapped signal 205_2.

A processor 3201 receives the control signal 200 and the mapped signal205_1. Since the generation of a modulated signal using the “method fortransmitting a modulated signal of a single stream” is designated by thecontrol signal 200, the processor 3201 generates and outputs processedsignals 3202_1 and 3202_2 corresponding to the mapped signal 205_1. Atthis time, it is assumed that the data included in the mapped signal205_1 is identical to the data included in the processed signal 3202_1,and the data included in the mapped signal 205_1 is identical to thedata included in the processed signal 3202_2.

The signal selector 3101 receives the control signal 200, the user #pprocessed signal 206_A, and the processed signal 3202_1. Since thegeneration of a modulated signal using the “method for transmitting amodulated signal of a single stream” is designated by the control signal200, the signal selector 3101 outputs the processed signal 3202_1 as theselected signal 206_A′. The selected signal 206_A′ corresponds to theuser #p first baseband signal 103_p_1 in FIG. 1 .

The signal selector 3203 receives the control signal 200, the user #pprocessed signal 206_B, and the processed signal 3202_2. Since thegeneration of a modulated signal using the “method for transmitting amodulated signal of a single stream” is designated by the control signal200, the signal selector 3203 outputs the processed signal 3202_2 as theselected signal 206_B′. The selected signal 206_B′ corresponds to theuser #p second baseband signal 103_p_2 in FIG. 1 .

A description has been given above of operation examples in the case ofgenerating multiple modulated signals including multiple streams and thecase of generating a modulated signal of a single stream in the user #psignal processor 102_p (p is an integer from 1 to M) in FIG. 1 by usingtwo example configurations. In the signal processors for individualusers in FIG. 1 , either of the above described generation of multiplemodulated signals including multiple streams and generation of amodulated signal of a single stream may be performed. In addition, asdescribed in the first embodiment and so forth, the signal processorsfor users in FIG. 1 do not necessarily output modulated signals.

First Supplement

In Expression (1) to Expression (42), an expression of a function of i(symbol number) is included. With reference to FIGS. 12 to 17 , adescription has been given that symbols may be arranged in the time-axisdirection, the frequency-axis direction, or the time-axis andfrequency-axis directions. Thus, an expression described as a functionof i in Expression (1) to Expression (42) may be interpreted as afunction of time, interpreted as a function of frequency, or interpretedas a function of time and frequency.

In this specification, for example, it is assumed that the transmissionapparatus in FIG. 1 is able to generate and transmit “modulated signalsusing the OFDM scheme and modulated signals of a single-carrier schemein a specific frequency band”. At this time, in a case where thetransmission apparatus in FIG. 1 transmits multiple modulated signals(baseband signals) for a certain user and performs phase change asdescribed in this specification, setting may be performed so that theperiod of phase change in the case of using the OFDM scheme is differentfrom the period of phase change in the case of using the single-carrierscheme. Since the frame configurations are different, it may bepreferable to perform setting so that the periods are different.However, the period of phase change in the case of using the OFDM schememay be identical to the period of phase change in the case of using thesingle-carrier scheme.

In addition, the user #1 signal processor 102_1 to the user #M signalprocessor 102_M in FIG. 1 may generate modulated signals of asingle-carrier or may generate modulated signals of a multi-carrierscheme such as the OFDM scheme, for example. Thus, single-carriermodulated signals and multi-carrier modulated signals such as the OFDMscheme may be transmitted from the transmission apparatus in FIG. 1 byusing identical times and identical frequencies (frequency bands thatoverlap each other at least partially).

For example, the user #1 signal processor 102_1 may generate the user #1baseband signal 103_1_1 corresponding to a modulated signal of thesingle-carrier scheme and the user #1 baseband signal 103_1_2corresponding to a modulated signal of the single-carrier scheme, theuser #2 signal processor 102_2 may generate the user #2 baseband signal103_2_1 corresponding to a modulated signal of the multi-carrier schemesuch as the OFDM scheme and the user #2 baseband signal 103_2_2corresponding to a modulated signal of the multi-carrier scheme such asthe OFDM scheme, and the transmission apparatus in FIG. 1 may transmit“the user #1 baseband signal 103_1_1 corresponding to a modulated signalof the single-carrier scheme and the user #1 baseband signal 103_1_2corresponding to a modulated signal of the single-carrier scheme” and“the user #2 baseband signal 103_2_1 corresponding to a modulated signalof the multi-carrier scheme such as the OFDM scheme and the user #2baseband signal 103_2_2 corresponding to a modulated signal of themulti-carrier scheme such as the OFDM scheme” at identical times andidentical frequencies (frequency bands that overlap each other at leastpartially). At this time, “the user #1 baseband signal 103_1_1corresponding to a modulated signal of the single-carrier scheme and theuser #1 baseband signal 103_1_2 corresponding to a modulated signal ofthe single-carrier scheme” may be baseband signals generated by usingany of the methods: “perform precoding and phase change”, “performprecoding”, “not perform precoding but perform phase change”, and“perform neither precoding nor phase change”. Likewise, “the user #2baseband signal 103_2_1 corresponding to a modulated signal of themulti-carrier scheme such as the OFDM scheme and the user #2 basebandsignal 103_2_2 corresponding to a modulated signal of the multi-carrierscheme such as the OFDM scheme” may be baseband signals generated byusing any of the methods: “perform precoding and phase change”, “performprecoding”, “not perform precoding but perform phase change”, and“perform neither precoding nor phase change”.

For another example, the user #1 signal processor 102_1 may generate abaseband signal of a single stream of the single-carrier scheme, theuser #2 signal processor 102_2 may generate the user #2 baseband signal103_2_1 corresponding to a modulated signal of the multi-carrier schemesuch as the OFDM scheme and the user #2 baseband signal 103_2_2corresponding to a modulated signal of the multi-carrier scheme such asthe OFDM scheme, and the transmission apparatus in FIG. 1 may transmit“the baseband signal of a single stream of the single-carrier scheme”and “the user #2 baseband signal 103_2_1 corresponding to a modulatedsignal of the multi-carrier scheme such as the OFDM scheme and the user#2 baseband signal 103_2_2 corresponding to a modulated signal of themulti-carrier scheme such as the OFDM scheme” at identical times andidentical frequencies (frequency bands that overlap each other at leastpartially). At this time, “the user #2 baseband signal 103_2_1corresponding to a modulated signal of the multi-carrier scheme such asthe OFDM scheme and the user #2 baseband signal 103_2_2 corresponding toa modulated signal of the multi-carrier scheme such as the OFDM scheme”may be baseband signals generated by using any of the methods: “performprecoding and phase change”, “perform precoding”, “not perform precodingbut perform phase change”, and “perform neither precoding nor phasechange”.

For another example, the user #1 signal processor 102_1 may generate theuser #1 baseband signal 103_1_1 corresponding to a modulated signal ofthe single-carrier scheme and the user #1 baseband signal 103_1_2corresponding to a modulated signal of the single-carrier scheme, theuser #2 signal processor 102_2 may generate a baseband signal of asingle stream of the multi-carrier scheme such as the OFDM scheme, andthe transmission apparatus in FIG. 1 may transmit “the user #1 basebandsignal 103_1_1 corresponding to a modulated signal of the single-carrierscheme and the user #1 baseband signal 103_1_2 corresponding to amodulated signal of the single-carrier scheme” and “the baseband signalof a single stream of the multi-carrier scheme such as the OFDM scheme”at identical times and identical frequencies (frequency bands thatoverlap each other at least partially). At this time, “the user #2baseband signal 103_2_1 corresponding to a modulated signal of themulti-carrier scheme such as the OFDM scheme and the user #2 basebandsignal 103_2_2 corresponding to a modulated signal of the multi-carrierscheme such as the OFDM scheme” may be baseband signals generated byusing any of the methods: “perform precoding and phase change”, “performprecoding”, “not perform precoding but perform phase change”, and“perform neither precoding nor phase change”.

For another example, the user #1 signal processor 102_1 may generate abaseband signal of a single stream of the single-carrier scheme, theuser #2 signal processor 102_2 may generate a baseband signal of asingle stream of the multi-carrier scheme such as the OFDM scheme, andthe transmission apparatus in FIG. 1 may transmit “the baseband signalof a single stream of the single-carrier scheme” and “the basebandsignal of a single stream of the multi-carrier scheme such as the OFDMscheme” at identical times and identical frequencies (frequency bandsthat overlap each other at least partially).

FIGS. 2 and 31 illustrate the configurations in which each user signalprocessor includes one error-correcting encoder and one mapper, but theconfiguration is not limited thereto. For example, a configurationincluding a first error-correcting encoder and a first mapper forgenerating the user #p mapped signal (baseband signal) 205_1 fortransmitting first data, and including a second error-correcting encoderand a second mapper for generating the user #p mapped signal (basebandsignal) 205_2 for transmitting second data may be adopted.Alternatively, the number of error-correcting encoders and the number ofmappers may be three.

Fifth Embodiment

In the present embodiment, a description will be given of an exampleoperation of a terminal by using the example described in the thirdembodiment. FIG. 34 is a diagram illustrating an example of theconfiguration of the terminal #p as a communication partner of the basestation in FIG. 24 . The terminal #p includes a transmission apparatus3403, a reception apparatus 3404, and a control signal generator 3408.

The transmission apparatus 3403 receives data 3401, a signal group 3402,and a control signal 3409. The transmission apparatus 3403 generates amodulated signal corresponding to the data 3401 and the signal group3402 and transmits the modulated signal from its antenna.

The reception apparatus 3404 receives a modulated signal transmitted bya communication partner, for example, the base station, performs signalprocessing, demodulation, and decoding on the modulated signal, andoutputs a control information signal 3405 and reception data 3406 fromthe communication partner.

The control signal generator 3408 receives the control informationsignal 3405 from the communication partner and a setting signal 3407. Onthe basis of these pieces of information, the control signal generator3408 generates the control signal 3409 and outputs it to thetransmission apparatus 3403.

FIG. 35 is a diagram illustrating an example of the configuration of thereception apparatus 3404 of the terminal #p illustrated in FIG. 34 . Thereception apparatus 3404 includes an antenna section 3501, a radiosection 3503, a channel estimator 3505, a signal processor 3509, and acontrol information decoder 3507.

The radio section 3503 receives a reception signal 3502 received by theantenna section 3501. The radio section 3503 performs processing such asfrequency conversion on the reception signal 3502 to generate a basebandsignal 3504. The radio section 3503 outputs the baseband signal 3504 tothe channel estimator 3505, the control information decoder 3507, andthe signal processor 3509.

The control information decoder 3507 receives the baseband signal 3504.The control information decoder 3507 outputs control information 3508,which is obtained by demodulating the control information symbolsincluded in the baseband signal 3504.

The channel estimator 3505 receives the baseband signal 3504. Thechannel estimator 3505 extracts a preamble and pilot symbols included inthe baseband signal 3504. The channel estimator 3505 estimates channelvariation on the basis of the preamble and the pilot symbols, andgenerates a channel estimation signal 3506 indicating the estimatedchannel variation. The channel estimator 3505 outputs the channelestimation signal 3506 to the signal processor 3509.

The signal processor 3509 receives the baseband signal 3504, the channelestimation signal 3506, and the control information 3508. On the basisof the channel estimation signal 3506 and the control information 3508,the signal processor 3509 performs demodulation and error-correctingdecoding on data symbols included in the baseband signal 3504, andgenerates reception data 3510. The signal processor 3509 outputs thereception data 3510.

FIG. 36 is a diagram illustrating an example of the frame configurationof a modulated signal of a single stream transmitted by using amulti-carrier transmission scheme such as the OFDM scheme. In FIG. 36 ,the horizontal axis indicates frequency and the vertical axis indicatestime. FIG. 36 illustrates, as an example, symbols from carrier 1 tocarrier 36. FIG. 36 also illustrates symbols from time 1 to time 11. Theframe configuration illustrated in FIG. 36 is an example of the frameconfiguration of a modulated signal of a single stream transmitted byusing a multi-carrier transmission scheme such as the OFDM scheme by thebase station (AP), which is a communication partner of the terminal #p.

In FIG. 36, 3601 denotes a pilot symbol, 3602 denotes a data symbol, and3603 denotes an other symbol. It is assumed that the pilot symbols 3601are symbols used by the terminal #p to estimate channel variation, forexample. It is assumed that the data symbols 3602 are symbols used bythe base station or AP to transmit data to the terminal #p. It isassumed that the other symbols 3603 include, for example, symbols usedby the terminal #p to perform signal detection, frequency offsetestimation, frequency synchronization, and time synchronization, and/orcontrol information symbols for demodulating the data symbols 3602(information about the transmission method, modulation scheme, anderror-correcting coding method of the data symbols 3602).

For example, the transmission apparatus of the base station in FIG. 1 or24 may transmit a modulated signal of a single stream having the frameconfiguration in FIG. 36 to the terminal #p.

FIG. 37 is a diagram illustrating an example of the frame configurationof a modulated signal of a single stream transmitted by using asingle-carrier transmission scheme. In FIG. 37 , the elements similar tothose in FIG. 10 are denoted by the same numerals. In FIG. 37 , thehorizontal axis indicates time, and FIG. 37 illustrates symbols fromtime t1 to t22. The frame configuration illustrated in FIG. 37 is anexample of the frame configuration of a modulated signal of a singlestream transmitted by using a single-carrier transmission scheme by thebase station or AP, which is a communication partner of the terminal #p.

For example, the transmission apparatus of the base station in FIG. 1 or24 may transmit a modulated signal of a single stream having the frameconfiguration in FIG. 37 to the terminal #p.

Also, for example, the transmission apparatus of the base station inFIG. 1 or 24 may transmit multiple modulated signals of multiple streamshaving the frame configurations in FIGS. 8 and 9 to the terminal #p.

Furthermore, for example, the transmission apparatus of the base stationin FIG. 1 or 24 may transmit multiple modulated signals of multiplestreams having the frame configurations in FIGS. 10 and 11 to theterminal #p.

Next, a description will be given of, using first to tenth examples, thereception capability in the reception apparatus of the terminal #pillustrated in FIG. 35 , that is, the schemes supported by the receptionapparatus, and the processing of the terminal #p and the processing ofthe base station (AP) based on the supported schemes.

First Example

As the first example, it is assumed that the reception apparatus of theterminal #p has the configuration illustrated in FIG. 35 and thereception apparatus of the terminal #p supports the following.

For example, the reception of “communication scheme #A” described in thethird embodiment is supported.

Thus, if the communication partner transmits multiple modulated signalsof multiple streams, the terminal #p does not support the reception ofthe modulated signals.

Thus, in a case where the communication partner performs phase changewhen transmitting multiple modulated signals of multiple streams, theterminal #p does not support the reception of the modulated signals.

Only the single-carrier scheme is supported.

Only the decoding of “error-correcting coding scheme #C” is supported asthe error-correcting coding scheme.

Thus, the terminal #p having the configuration in FIG. 35 and supportingthe above generates the reception capability notification symbol 2702illustrated in FIG. 30 on the basis of the rules described in the thirdembodiment and transmits the reception capability notification symbol2702 in accordance with the procedure in FIG. 27 , for example.

At this time, the terminal #p generates the reception capabilitynotification symbol 2702 illustrated in FIG. 30 in the transmissionapparatus 3403 in FIG. 34 , for example. Subsequently, the transmissionapparatus 3403 in FIG. 34 transmits the reception capabilitynotification symbol 2702 illustrated in FIG. 30 in accordance with theprocedure in FIG. 27 .

The signal processor 155 of the base station (AP) in FIG. 22 obtains thebaseband signal group 154 including the reception capabilitynotification symbol 2702 transmitted by the terminal #p, through thereception antenna group 151 and the radio section group 153.Subsequently, the signal processor 155 of the base station (AP) in FIG.22 extracts the data included in the reception capability notificationsymbol 2702 and learns, from the data 3001 about “supported schemes”(see FIG. 30 ), that the terminal #p supports “communication scheme #A”.

Thus, the signal processor 155 of the base station determines not totransmit a modulated signal whose phase has been changed because thedata 2801 about “support/not support phase demodulation of modulatedsignal with phase change” in FIG. 30 is invalid and the communicationscheme #A is supported, and outputs the control information 157 (seeFIG. 22 ) including this information. This is because the communicationscheme #A does not support the transmission and reception of multiplemodulated signals for multiple streams.

In addition, the signal processor 155 of the base station determines notto transmit multiple modulated signals for multiple streams because thedata 2901 about “support/not support reception for multiple streams” inFIG. 30 is invalid and the communication scheme #A is supported, andoutputs the control information 157 including this information. This isbecause the communication scheme #A does not support the transmissionand reception of multiple modulated signals for multiple streams.

In addition, the signal processor 155 of the base station determines touse “error-correcting coding scheme #C” because the data 3003 about“supported error-correcting coding schemes” in FIG. 30 is invalid andthe communication scheme #A is supported, and outputs the controlinformation 157 including this information. This is because thecommunication scheme #A supports “error-correcting coding scheme #C”.

For example, as in FIG. 35 , “communication scheme #A” is supported, andthus the base station or AP performs the above-described operations soas not to transmit multiple modulated signals for multiple streams.Thus, the base station (AP) appropriately transmits a modulated signalof “communication scheme #A”, and accordingly the data transmissionefficiency in the system constituted by the base station (AP) and theterminal #p can be increased.

Second Example

As the second example, it is assumed that the reception apparatus of theterminal #p has the configuration illustrated in FIG. 35 and thereception apparatus of the terminal #p supports the following.

For example, the reception of “communication scheme #B” described in thethird embodiment is supported.

Since the reception apparatus has the configuration illustrated in FIG.35 , if the communication partner transmits multiple modulated signalsof multiple streams, the terminal #p does not support the reception ofthe modulated signals.

Thus, in a case where the communication partner performs phase changewhen transmitting multiple modulated signals of multiple streams, theterminal #p does not support the reception of the modulated signals.

The single-carrier scheme and the multi-carrier scheme such as the OFDMscheme are supported.

The decoding of “error-correcting coding scheme #C” and“error-correcting coding scheme #D” are supported as theerror-correcting coding scheme.

Thus, the terminal #p having the configuration in FIG. 35 and supportingthe above generates the reception capability notification symbol 2702illustrated in FIG. 30 on the basis of the rules described in the thirdembodiment and transmits the reception capability notification symbol2702 in accordance with the procedure in FIG. 27 , for example.

At this time, the terminal #p generates the reception capabilitynotification symbol 2702 illustrated in FIG. 30 in the transmissionapparatus 3403 in FIG. 34 , for example. Subsequently, the transmissionapparatus 3403 in FIG. 34 transmits the reception capabilitynotification symbol 2702 illustrated in FIG. 30 in accordance with theprocedure in FIG. 27 .

The signal processor 155 of the base station (AP) in FIG. 22 obtains thebaseband signal group 154 including the reception capabilitynotification symbol 2702 transmitted by the terminal #p, through thereception antenna group 151 and the radio section group 153.Subsequently, the signal processor 155 of the base station (AP) in FIG.22 extracts the data included in the reception capability notificationsymbol 2702 and learns, from the data 3001 about “supported schemes”,that the terminal #p supports “communication scheme #B”.

Also, the signal processor 155 of the base station learns, from the data2901 about “support/not support reception for multiple streams” in FIG.30 , that the terminal #p as a communication partner is unable todemodulate multiple modulated signals for multiple streams.

Thus, the signal processor 155 of the base station determines that thedata 2801 about “support/not support demodulation of modulated signalwith phase change” in FIG. 30 is invalid and determines not to transmita modulated signal whose phase has been changed, and outputs the controlinformation 157 including this information. This is because the terminal#p does not support “reception for multiple streams”.

In addition, on the basis of the data 3002 about “support/not supportmulti-carrier scheme” in FIG. 30 , the signal processor 155 of the basestation outputs the control information 157 including information aboutwhether the terminal #p as a communication partner supports themulti-carrier scheme and/or supports the single-carrier scheme.

In addition, on the basis of the data 3003 about “supportederror-correcting coding schemes” in FIG. 30 , the signal processor 155of the base station outputs the control information 157 includinginformation about whether the terminal #p as a communication partnersupports “error-correcting coding scheme #C” and/or “error-correctingcoding scheme #D”.

Thus, the base station (AP) performs the above-described operations soas not to transmit multiple modulated signals for multiple streams,thereby being able to appropriately transmit a modulated signal of asingle stream. Accordingly, the data transmission efficiency in thesystem constituted by the base station (AP) and the terminal #p can beincreased.

Third Example

As the third example, it is assumed that the reception apparatus of theterminal #p has the configuration illustrated in FIG. 35 and thereception apparatus of the terminal #p supports the following.

The reception of “communication scheme #A” and the reception of“communication scheme #B” described in the third embodiment aresupported.

In both “communication scheme #A” and “communication scheme #B”, if thecommunication partner transmits multiple modulated signals of multiplestreams, the terminal #p does not support the reception of the modulatedsignals.

Thus, in a case where the communication partner performs phase changewhen transmitting multiple modulated signals of multiple streams, theterminal #p does not support the reception of the modulated signals.

In both “communication scheme #A” and “communication scheme #B”, onlythe single-carrier scheme is supported.

Regarding the error-correcting coding scheme, the decoding of“error-correcting coding scheme #C” is supported as “communicationscheme #A”, and the decoding of “error-correcting coding scheme #C” and“error-correcting coding scheme #D” is supported as “communicationscheme #B”.

Thus, the terminal #p having the configuration in FIG. 35 and supportingthe above generates the reception capability notification symbol 2702illustrated in FIG. 30 on the basis of the rules described in the thirdembodiment and transmits the reception capability notification symbol2702 in accordance with the procedure in FIG. 27 , for example.

At this time, the terminal #p generates the reception capabilitynotification symbol 2702 illustrated in FIG. 30 in the transmissionapparatus 3403 in FIG. 34 , for example. Subsequently, the transmissionapparatus 3403 in FIG. 34 transmits the reception capabilitynotification symbol 2702 illustrated in FIG. 30 in accordance with theprocedure in FIG. 27 .

The signal processor 155 of the base station (AP) in FIG. 22 obtains thebaseband signal group 154 including the reception capabilitynotification symbol 2702 transmitted by the terminal #p, through thereception antenna group 151 and the radio section group 153.Subsequently, the signal processor 155 of the base station (AP) in FIG.22 extracts the data included in the reception capability notificationsymbol 2702 and learns, from the data 3001 about “supported schemes”,that the terminal #p supports “communication scheme #A” and“communication scheme #B”.

Also, the signal processor 155 of the base station learns, from the data2901 about “support/not support reception for multiple streams” in FIG.30 , that the terminal #p “does not support reception for multiplestreams”.

Thus, the signal processor 155 of the base station determines not totransmit a modulated signal whose phase has been changed because thedata 2801 about “support/not support demodulation of modulated signalwith phase change” in FIG. 30 is invalid and the communication scheme #Ais supported, and outputs the control information 157 including thisinformation. This is because the terminal #p does not support thetransmission and reception of multiple modulated signals for multiplestreams.

Also, the signal processor 155 of the base station learns, from the data3002 about “support/not support multi-carrier scheme” in FIG. 30 ,whether the terminal #p supports the single-carrier scheme or themulti-carrier scheme such as the OFDM scheme.

In addition, the signal processor 155 of the base station learns, fromthe data 3003 about “supported error-correcting coding schemes” in FIG.30 , that the terminal #p supports the decoding of “error-correctingcoding scheme #C” and “error-correcting coding scheme #D”.

Thus, the base station (AP) performs the above-described operations soas not to transmit multiple modulated signals for multiple streams,thereby being able to appropriately transmit a modulated signal of asingle stream. Accordingly, the data transmission efficiency in thesystem constituted by the base station (AP) and the terminal #p can beincreased.

Fourth Example

As the fourth example, it is assumed that the reception apparatus of theterminal #p has the configuration illustrated in FIG. 35 and thereception apparatus of the terminal #p supports the following.

The reception of “communication scheme #A” and the reception of“communication scheme #B” described in the third embodiment aresupported.

In both “communication scheme #A” and “communication scheme #B”, if thecommunication partner transmits multiple modulated signals of multiplestreams, the terminal #p does not support the reception of the modulatedsignals.

Thus, in a case where the communication partner performs phase changewhen transmitting multiple modulated signals of multiple streams, theterminal #p does not support the reception of the modulated signals.

The single-carrier scheme is supported as “communication scheme #A”, andthe single-carrier scheme and the multi-carrier scheme such as the OFDMscheme are supported as “communication scheme #B”.

Regarding the error-correcting coding scheme, the decoding of“error-correcting coding scheme #C” is supported as “communicationscheme #A”, and the decoding of “error-correcting coding scheme #C” and“error-correcting coding scheme #D” is supported as “communicationscheme #B”.

Thus, the terminal #p having the configuration in FIG. 35 and supportingthe above generates the reception capability notification symbol 2702illustrated in FIG. 30 on the basis of the rules described in the thirdembodiment and transmits the reception capability notification symbol2702 in accordance with the procedure in FIG. 27 , for example.

The signal processor 155 of the base station (AP) in FIG. 22 obtains thebaseband signal group 154 including the reception capabilitynotification symbol 2702 transmitted by the terminal #p, through thereception antenna group 151 and the radio section group 153.Subsequently, the signal processor 155 of the base station (AP) in FIG.22 extracts the data included in the reception capability notificationsymbol 2702 and learns, from the data 3001 about “supported schemes”,that the terminal #p supports “communication scheme #A” and“communication scheme #B”.

Also, the signal processor 155 of the base station learns, from the data2901 about “support/not support reception for multiple streams” in FIG.30 , that the terminal #p “does not support reception for multiplestreams”.

Thus, the signal processor 155 of the base station determines not totransmit a modulated signal whose phase has been changed because thedata 2801 about “support/not support demodulation of modulated signalwith phase change” in FIG. 30 is invalid and the communication scheme #Ais supported, and outputs the control information 157 including thisinformation. This is because the terminal #p does not support thetransmission and reception of multiple modulated signals for multiplestreams.

The signal processor 155 of the base station learns, from the data 3002about “support/not support multi-carrier scheme” in FIG. 30 , whetherthe terminal #p supports the single-carrier scheme or the multi-carrierscheme such as the OFDM scheme.

At this time, the data 3002 about “support/not support multi-carrierscheme” needs the configuration described below, for example.

The data 3002 about “support/not support multi-carrier scheme” is madeup of 4 bits, and the 4 bits are represented by g0, g1, g2, and g3. Atthis time, the terminal #p sets g0, g1, g2, and g3 in the followingmanner in accordance with the reception capability of the terminal #pand transmits the data 3002 about “support/not support multi-carrierscheme”.

In a case where the terminal #p supports the demodulation of thesingle-carrier scheme regarding “communication scheme #A”, the terminal#p sets (g0, g1)=(0, 0).

In a case where the terminal #p supports the demodulation of themulti-carrier scheme such as OFDM regarding “communication scheme #A”,the terminal #p sets (g0, g1)=(0, 1).

In a case where the terminal #p supports the demodulation of thesingle-carrier scheme and demodulation of the multi-carrier scheme suchas OFDM regarding “communication scheme #A”, the terminal #p sets (g0,g1)=(1, 1).

In a case where the terminal #p supports the demodulation of thesingle-carrier scheme regarding “communication scheme #B”, the terminal#p sets (g2, g3)=(0, 0).

In a case where the terminal #p supports the demodulation of themulti-carrier scheme such as OFDM regarding “communication scheme #B”,the terminal #p sets (g2, g3)=(0, 1).

In a case where the terminal #p supports the demodulation of thesingle-carrier scheme and demodulation of the multi-carrier scheme suchas OFDM regarding “communication scheme #B”, the terminal #p sets (g2,g3)=(1, 1).

In addition, the signal processor 155 of the base station learns, fromthe data 3003 about “supported error-correcting coding schemes” in FIG.30 , that the terminal #p supports the decoding of “error-correctingcoding scheme #C” and “error-correcting coding scheme #D”.

Thus, the base station (AP) performs the above-described operations soas not to transmit multiple modulated signals for multiple streams,thereby being able to appropriately transmit a modulated signal of asingle stream. Accordingly, the data transmission efficiency in thesystem constituted by the base station (AP) and the terminal #p can beincreased.

Fifth Example

As the fifth example, it is assumed that the reception apparatus of theterminal #p has the configuration illustrated in FIG. 19 and thereception apparatus of the terminal #p supports the following, forexample.

For example, the reception of “communication scheme #A” and“communication scheme #B” described in the third embodiment issupported.

In “communication scheme #B”, if the communication partner transmitsmultiple modulated signals of multiple streams, the terminal #p supportsthe reception of the modulated signals. In “communication scheme #A” and“communication scheme #B”, if the communication partner transmits amodulated signal of a single stream, the terminal #p supports thereception of the modulated signal.

In a case where the communication partner performs phase change whentransmitting modulated signals of multiple streams, the terminal #psupports the reception of the modulated signals.

Only the single-carrier scheme is supported.

Only the decoding of “error-correcting coding scheme #C” is supported asthe error-correcting coding scheme.

Thus, the terminal #p having the configuration in FIG. 19 and supportingthe above generates the reception capability notification symbol 2702illustrated in FIG. 30 on the basis of the rules described in the thirdembodiment and transmits the reception capability notification symbol2702 in accordance with the procedure in FIG. 27 , for example.

At this time, the terminal #p generates the reception capabilitynotification symbol 2702 illustrated in FIG. 30 in the transmissionapparatus 3403 in FIG. 34 , for example, and the transmission apparatus3403 in FIG. 34 transmits the reception capability notification symbol2702 illustrated in FIG. 30 in accordance with the procedure in FIG. 27.

The signal processor 155 of the base station (AP) in FIG. 22 obtains thebaseband signal group 154 including the reception capabilitynotification symbol 2702 transmitted by the terminal #p, through thereception antenna group 151 and the radio section group 153.Subsequently, the signal processor 155 of the base station (AP) in FIG.22 extracts the data included in the reception capability notificationsymbol 2702 and learns, from the data 3001 about “supported schemes”,that the terminal #p supports “communication scheme #A” and“communication scheme #B”.

In addition, the signal processor 155 of the base station learns, fromthe data 2901 about “support/not support reception for multiple streams”in FIG. 30 , that “if the communication partner transmits multiplemodulated signals of multiple streams in “communication scheme #B”, theterminal #p supports the reception of the modulated signals“. Also, thesignal processor 155 of the base station learns, from the data 2901about “support/not support reception for multiple streams” in FIG. 30 ,that “if the communication partner transmits a modulated signal of asingle stream in “communication scheme #A” and “communication scheme#B”, the terminal #p supports the reception of the modulated signal“.

Also, the signal processor 155 of the base station learns, from the data2801 about “support/not support demodulation of modulated signal withphase change” in FIG. 30 , that the terminal #p “supports phase changedemodulation”.

The signal processor 155 of the base station learns, from the data 3002about “support/not support multi-carrier scheme” in FIG. 30 , that theterminal #p “supports only the single-carrier scheme”.

The signal processor 155 of the base station learns, from the data 3003about “supported error-correcting coding schemes” in FIG. 30 , that theterminal #p “supports only the decoding of “error-correcting codingscheme #C””.

Thus, the base station (AP) appropriately generates and transmits amodulated signal that can be received by the terminal #p inconsideration of a communication scheme supported by the terminal #p anda communication environment, and accordingly the data transmissionefficiency in the system constituted by the base station (AP) and theterminal #p can be increased.

Sixth Example

As the sixth example, it is assumed that the reception apparatus of theterminal #p has the configuration illustrated in FIG. 19 and thereception apparatus of the terminal #p supports the following, forexample.

For example, the reception of “communication scheme #A” and“communication scheme #B” described in the third embodiment issupported.

In “communication scheme #B”, if the communication partner transmitsmultiple modulated signals of multiple streams, the terminal #p supportsthe reception of the modulated signals. In “communication scheme #A” and“communication scheme #B”, if the communication partner transmits amodulated signal of a single stream, the terminal #p supports thereception of the modulated signal.

In a case where the communication partner performs phase change whentransmitting modulated signals of multiple streams, the terminal #p doesnot support the reception of the modulated signals.

Only the single-carrier scheme is supported.

The decoding of “error-correcting coding scheme #C” and the decoding of“error-correcting coding scheme #D” are supported as theerror-correcting coding scheme.

Thus, the terminal #p having the configuration in FIG. 19 and supportingthe above generates the reception capability notification symbol 2702illustrated in FIG. 30 on the basis of the rules described in the thirdembodiment and transmits the reception capability notification symbol2702 in accordance with the procedure in FIG. 27 , for example.

At this time, the terminal #p generates the reception capabilitynotification symbol 2702 illustrated in FIG. 30 in the transmissionapparatus 3403 in FIG. 34 , for example, and the transmission apparatus3403 in FIG. 34 transmits the reception capability notification symbol2702 illustrated in FIG. 30 in accordance with the procedure in FIG. 27.

The signal processor 155 of the base station (AP) in FIG. 22 obtains thebaseband signal group 154 including the reception capabilitynotification symbol 2702 transmitted by the terminal #p, through thereception antenna group 151 and the radio section group 153.Subsequently, the signal processor 155 of the base station (AP) in FIG.22 extracts the data included in the reception capability notificationsymbol 2702 and learns, from the data 3001 about “supported schemes”,that the terminal #p supports “communication scheme #A” and“communication scheme #B”.

In addition, the signal processor 155 of the base station learns, fromthe data 2901 about “support/not support reception for multiple streams”in FIG. 30 , that “if the communication partner transmits multiplemodulated signals of multiple streams in “communication scheme #B”, theterminal #p supports the reception of the modulated signals“. Also, thesignal processor 155 of the base station learns, from the data 2901about “support/not support reception for multiple streams” in FIG. 30 ,that “if the communication partner transmits a modulated signal of asingle stream in “communication scheme #A” and “communication scheme#B”, the terminal #p supports the reception of the modulated signal“.

Also, the signal processor 155 of the base station learns, from the data2801 about “support/not support demodulation of modulated signal withphase change” in FIG. 30 , that the terminal #p “does not support phasechange demodulation”. Thus, the base station (AP) transmits multiplemodulated signals of multiple streams to the terminal #p withoutperforming phase change.

The signal processor 155 of the base station learns, from the data 3002about “support/not support multi-carrier scheme” in FIG. 30 , that theterminal #p “supports only the single-carrier scheme”.

The signal processor 155 of the base station learns, from the data 3003about “supported error-correcting coding schemes” in FIG. 30 , that theterminal #p “supports the decoding of “error-correcting coding scheme#C” and the decoding of “error-correcting coding scheme #D””.

Thus, the base station (AP) appropriately generates and transmits amodulated signal that can be received by the terminal #p inconsideration of a communication scheme supported by the terminal #p anda communication environment, and accordingly the data transmissionefficiency in the system constituted by the base station (AP) and theterminal #p can be increased.

Seventh Example

As the seventh example, it is assumed that the reception apparatus ofthe terminal #p has the configuration illustrated in FIG. 19 and thereception apparatus of the terminal #p supports the following, forexample.

For example, the reception of “communication scheme #A” and“communication scheme #B” described in the third embodiment issupported.

In “communication scheme #B”, if the communication partner transmitsmultiple modulated signals of multiple streams, the terminal #p supportsthe reception of the modulated signals. In “communication scheme #A” and“communication scheme #B”, if the communication partner transmits amodulated signal of a single stream, the terminal #p supports thereception of the modulated signal.

The single-carrier scheme is supported as “communication scheme #A”, andthe single-carrier scheme and the multi-carrier scheme such as the OFDMscheme are supported as “communication scheme #B”. However, it isassumed that, only in the case of the multi-carrier scheme such as theOFDM scheme in “communication scheme #B”, “the communication partner isable to perform phase change when transmitting modulated signals ofmultiple streams”.

In a case where the communication partner performs phase change whentransmitting modulated signals of multiple streams, the terminal #psupports the reception of the modulated signals.

The decoding of “error-correcting coding scheme #C” and the decoding of“error-correcting coding scheme #D” are supported as theerror-correcting coding scheme.

Thus, the terminal #p having the configuration in FIG. 19 and supportingthe above generates the reception capability notification symbol 2702illustrated in FIG. 30 on the basis of the rules described in the thirdembodiment and the present embodiment, and transmits the receptioncapability notification symbol 2702 in accordance with the procedure inFIG. 27 , for example.

At this time, the terminal #p generates the reception capabilitynotification symbol 2702 illustrated in FIG. 30 in the transmissionapparatus 3403 in FIG. 34 , for example, and the transmission apparatus3403 in FIG. 34 transmits the reception capability notification symbol2702 illustrated in FIG. 30 in accordance with the procedure in FIG. 27.

The signal processor 155 of the base station (AP) in FIG. 22 obtains thebaseband signal group 154 including the reception capabilitynotification symbol 2702 transmitted by the terminal #p, through thereception antenna group 151 and the radio section group 153.Subsequently, the signal processor 155 of the base station (AP) in FIG.22 extracts the data included in the reception capability notificationsymbol 2702 and learns, from the data 3001 about “supported schemes”,that the terminal #p supports “communication scheme #A” and“communication scheme #B”.

In addition, the signal processor 155 of the base station learns, fromthe data 2901 about “support/not support reception for multiple streams”in FIG. 30 , that “if the communication partner transmits multiplemodulated signals of multiple streams in “communication scheme #B”, theterminal #p supports the reception of the modulated signals“. Inaddition, the signal processor 155 of the base station learns, from thedata 2901 about “support/not support reception for multiple streams” inFIG. 30 , that “if the communication partner transmits a modulatedsignal of a single stream in “communication scheme #A” and“communication scheme #B”, the terminal #p supports the reception of themodulated signal“.

Also, the signal processor 155 of the base station learns, from the data2801 about “support/not support demodulation of modulated signal withphase change” in FIG. 30 , that the terminal #p “does not support phasechange demodulation”. Thus, the base station (AP) transmits multiplemodulated signals of multiple streams to the terminal #p withoutperforming phase change. When the terminal #p obtains information“support phase change demodulation” from the data 2801 about“support/not support demodulation of modulated signal with phase change”as described above, the terminal #p understands that it is only in“communication scheme #B”.

The signal processor 155 of the base station learns, from the data 3002about “support/not support multi-carrier scheme” in FIG. 30 , that theterminal #p supports the single-carrier scheme as “communication scheme#A” and supports the single-carrier scheme and the multi-carrier schemesuch as the OFDM scheme as “communication scheme #B”. At this time, asdescribed above, the terminal #p may preferably notify the base stationor AP of the situation of supporting the single-carrier scheme and themulti-carrier scheme such as OFDM in “communication scheme #A” andsupporting the single-carrier scheme and the multi-carrier scheme suchas OFDM in “communication scheme #B”.

The signal processor 155 of the base station learns, from the data 3003about “supported error-correcting coding schemes” in FIG. 30 , that theterminal #p “supports the decoding of “error-correcting coding scheme#C” and the decoding of “error-correcting coding scheme #D””.

Thus, the base station (AP) appropriately generates and transmits amodulated signal that can be received by the terminal #p inconsideration of a communication scheme supported by the terminal #p anda communication environment, and accordingly the data transmissionefficiency in the system constituted by the base station (AP) and theterminal #p can be increased.

Eighth Example

As the eighth example, it is assumed that the reception apparatus of theterminal #p has the configuration illustrated in FIG. 19 and thereception apparatus of the terminal #p supports the following, forexample.

For example, the reception of “communication scheme #A” and“communication scheme #B” described in the third embodiment issupported.

In “communication scheme #B”, if the communication partner transmitsmultiple modulated signals of multiple streams, the terminal #p supportsthe reception of the modulated signals. In “communication scheme #A” and“communication scheme #B”, if the communication partner transmits amodulated signal of a single stream, the terminal #p supports thereception of the modulated signal.

In the single-carrier scheme in “communication scheme #B”, if thecommunication partner transmits multiple modulated signals of multiplestreams, the terminal #p supports the reception of the modulatedsignals. On the other hand, in the multi-carrier scheme such as OFDM in“communication scheme #B”, if the communication partner transmitsmultiple modulated signals of multiple streams, the terminal #p does notsupport the reception of the modulated signals.

In the single-carrier scheme in “communication scheme #A”, when thecommunication partner transmits a modulated signal of a single stream,the terminal #p supports the reception of the modulated signal. Thereception of the multi-carrier scheme such as the OFDM scheme is notsupported.

In a case where the communication partner performs phase change whentransmitting modulated signals of multiple streams, the terminal #psupports the reception of the modulated signals.

The decoding of “error-correcting coding scheme #C” and the decoding of“error-correcting coding scheme #D” are supported as theerror-correcting coding scheme.

Thus, the terminal #p having the configuration in FIG. 19 and supportingthe above generates the reception capability notification symbol 2702illustrated in FIG. 30 on the basis of the rules described in the thirdembodiment and transmits the reception capability notification symbol2702 in accordance with the procedure in FIG. 27 , for example.

At this time, the terminal #p generates the reception capabilitynotification symbol 2702 illustrated in FIG. 30 in the transmissionapparatus 3403 in FIG. 34 , for example, and the transmission apparatus3403 in FIG. 34 transmits the reception capability notification symbol2702 illustrated in FIG. 30 in accordance with the procedure in FIG. 27.

The signal processor 155 of the base station (AP) in FIG. 22 obtains thebaseband signal group 154 including the reception capabilitynotification symbol 2702 transmitted by the terminal #p, through thereception antenna group 151 and the radio section group 153.Subsequently, the signal processor 155 of the base station (AP) in FIG.22 extracts the data included in the reception capability notificationsymbol 2702 and learns, from the data 3001 about “supported schemes”,that the terminal #p supports “communication scheme #A” and“communication scheme #B”.

In addition, the signal processor 155 of the base station learns, fromthe data 2901 about “support/not support reception for multiple streams”in FIG. 30 , that “if the base station transmits multiple modulatedsignals of multiple streams in the single-carrier scheme of“communication scheme #B”, the terminal #p supports the reception of themodulated signals“. In addition, the signal processor 155 of the basestation learns, from the data 2901 about “support/not support receptionfor multiple streams” in FIG. 30 , that “if the base station transmitsmultiple modulated signals of multiple streams in the multi-carrierscheme such as OFDM of “communication scheme #B”, the terminal #p doesnot support the reception of the modulated signals“. In addition, thesignal processor 155 of the base station learns, from the data 2901about “support/not support reception for multiple streams” in FIG. 30 ,that “if the base station transmits a modulated signal of a singlestream in “communication scheme #A” and “communication scheme #B”, theterminal #p supports the reception of the modulated signal“.

At this time, the data 2901 about “support/not support reception formultiple streams” needs the data configuration described below, forexample.

The data 2901 about “support/not support reception for multiple streams”is made up of 2 bits, and the 2 bits are represented by h0 and h1.

In a case where the terminal #p supports the demodulation of multiplemodulated signals of multiple streams transmitted by the communicationpartner in the single-carrier scheme of “communication scheme #B”, theterminal #p sets h0=1. If the terminal #p does not support thedemodulation, the terminal #p sets h0=0.

In a case where the terminal #p supports the demodulation of multiplemodulated signals of multiple streams transmitted by the communicationpartner in the multi-carrier scheme such as OFDM of “communicationscheme #B”, the terminal #p sets h1=1. If the terminal #p does notsupport the demodulation, the terminal #p sets h1=0.

The signal processor 155 of the base station learns, from the data 2801about “support/not support demodulation of modulated signal with phasechange” in FIG. 30 , that the terminal #p “supports phase changedemodulation”.

The signal processor 155 of the base station learns, from the data 3002about “support/not support multi-carrier scheme” in FIG. 30 , that theterminal #p “supports only the single-carrier scheme”.

The signal processor 155 of the base station learns, from the data 3003about “supported error-correcting coding schemes” in FIG. 30 , that theterminal #p supports the decoding of “error-correcting coding scheme #C”and “error-correcting coding scheme #D”.

Thus, the base station (AP) appropriately generates and transmits amodulated signal that can be received by the terminal #p inconsideration of a communication scheme supported by the terminal #p anda communication environment, and accordingly the data transmissionefficiency in the system constituted by the base station (AP) and theterminal #p can be increased.

Ninth Example

As the ninth example, it is assumed that the reception apparatus of theterminal #p has the configuration illustrated in FIG. 19 and thereception apparatus of the terminal #p supports the following, forexample.

For example, the reception of “communication scheme #A” and“communication scheme #B” described in the third embodiment issupported.

In “communication scheme #B”, if the communication partner transmitsmultiple modulated signals of multiple streams, the terminal #p supportsthe reception of the modulated signals. In “communication scheme #A” and“communication scheme #B”, if the communication partner transmits amodulated signal of a single stream, the terminal #p supports thereception of the modulated signal.

In “communication scheme #B”, the base station (AP) as a communicationpartner is able to transmit multiple modulated signals for multiplestreams in the single-carrier scheme and the multi-carrier scheme suchas OFDM. However, the communication partner is able to perform phasechange when transmitting multiple modulated signals of multiple streamsonly in the multi-carrier scheme such as the OFDM scheme of“communication scheme #B”. In a case where the communication partnerperforms phase change when transmitting multiple modulated signals ofmultiple streams, the terminal #p supports the reception of themodulated signals.

The decoding of “error-correcting coding scheme #C” and the decoding of“error-correcting coding scheme #D” are supported as theerror-correcting coding scheme.

Thus, the terminal #p having the configuration in FIG. 19 and supportingthe above generates the reception capability notification symbol 2702illustrated in FIG. 30 on the basis of the rules described in the thirdembodiment and transmits the reception capability notification symbol2702 in accordance with the procedure in FIG. 27 , for example.

At this time, the terminal #p generates the reception capabilitynotification symbol 2702 illustrated in FIG. 30 in the transmissionapparatus 3403 in FIG. 34 , for example, and the transmission apparatus3403 in FIG. 34 transmits the reception capability notification symbol2702 illustrated in FIG. 30 in accordance with the procedure in FIG. 27.

The signal processor 155 of the base station (AP) in FIG. 22 obtains thebaseband signal group 154 including the reception capabilitynotification symbol 2702 transmitted by the terminal #p, through thereception antenna group 151 and the radio section group 153.Subsequently, the signal processor 155 of the base station in FIG. 22extracts the data included in the reception capability notificationsymbol 2702 and learns, from the data 3001 about “supported schemes”,that the terminal #p supports “communication scheme #A” and“communication scheme #B”.

The signal processor 155 of the base station learns, from the data 2901about “support/not support reception for multiple streams” in FIG. 30 ,that “if the communication partner transmits multiple modulated signalsof multiple streams in “communication scheme #B”, the terminal #psupports the reception of the modulated signals“. Also, the signalprocessor 155 of the base station learns, from the data 2901 about“support/not support reception for multiple streams” in FIG. 30 , that“if the communication partner transmits a modulated signal of a singlestream in “communication scheme #A” and “communication scheme #B”, theterminal #p supports the reception of the modulated signal“.

In addition, the signal processor 155 of the base station learns, fromthe data 3002 about “support/not support multi-carrier scheme” in FIG.30 , whether the terminal #p supports “single-carrier scheme”, supports“multi-carrier scheme such as OFDM”, or supports “both thesingle-carrier scheme and the multi-carrier scheme such as OFDM”.

When the signal processor 155 of the base station learns that theterminal #p “supports the single-carrier scheme”, the signal processor155 of the base station interprets that the data 2801 about “support/notsupport demodulation of modulated signal with phase change” in FIG. 30is invalid and interprets that “phase change demodulation is notsupported”. This is because the base station as a communication partnerdoes not support phase change at the time of the single-carrier scheme.

When the signal processor 155 of the base station learns that theterminal #p “supports the multi-carrier scheme such as OFDM” or“supports both the single-carrier scheme and the multi-carrier schemesuch as OFDM”, the signal processor 155 of the base station does notinterpret that the data 2801 about “support/not support demodulation ofmodulated signal with phase change” in FIG. 30 is invalid (i.e.,interprets that the data 2801 is valid). The signal processor 155 of thebase station obtains, from the data 2801 about “support/not supportdemodulation of modulated signal with phase change” in FIG. 30 ,information indicating whether or not the terminal #p supports phasechange demodulation in the multi-carrier scheme such as OFDM.

The signal processor 155 of the base station learns, from the data 3003about “supported error-correcting coding schemes” in FIG. 30 , that theterminal #p “supports the decoding of “error-correcting coding scheme#C” and the decoding of “error-correcting coding scheme #D””.

Thus, the base station (AP) appropriately generates and transmits amodulated signal that can be received by the terminal #p inconsideration of a communication scheme supported by the terminal #p anda communication environment, and accordingly the data transmissionefficiency in the system constituted by the base station (AP) and theterminal #p can be increased.

Tenth Example

As the tenth example, it is assumed that the reception apparatus of theterminal #p has the configuration illustrated in FIG. 19 and thereception apparatus of the terminal #p supports the following, forexample.

For example, the reception of “communication scheme #A” and“communication scheme #B” described in the third embodiment issupported.

In “communication scheme #B”, if the communication partner transmitsmultiple modulated signals of multiple streams, the terminal #p supportsthe reception of the modulated signals. In “communication scheme #A” and“communication scheme #B”, if the communication partner transmits amodulated signal of a single stream, the terminal #p supports thereception of the modulated signal.

In “communication scheme #B”, the base station or AP is able to transmitmultiple modulated signals for multiple streams in the single-carrierscheme and the multi-carrier scheme such as OFDM.

In the single-carrier scheme, when the communication partner transmitsmodulated signals of multiple streams, whether or not to perform phasechange can be set. In the multi-carrier scheme such as OFDM, when thecommunication partner transmits modulated signals of multiple streams,whether or not to perform phase change can be set.

The decoding of “error-correcting coding scheme #C” and the decoding of“error-correcting coding scheme #D” are supported as theerror-correcting coding scheme.

Thus, the terminal #p having the configuration in FIG. 19 and supportingthe above generates the reception capability notification symbol 2702illustrated in FIG. 30 on the basis of the rules described in the thirdembodiment and transmits the reception capability notification symbol2702 in accordance with the procedure in FIG. 27 , for example.

At this time, the terminal #p generates the reception capabilitynotification symbol 2702 illustrated in FIG. 30 in the transmissionapparatus 3403 in FIG. 34 , for example, and the transmission apparatus3403 in FIG. 34 transmits the reception capability notification symbol2702 illustrated in FIG. 30 in accordance with the procedure in FIG. 27.

The signal processor 155 of the base station (AP) in FIG. 22 obtains thebaseband signal group 154 including the reception capabilitynotification symbol 2702 transmitted by the terminal #p, through thereception antenna group 151 and the radio section group 153.Subsequently, the signal processor 155 of the base station (AP) in FIG.22 extracts the data included in the reception capability notificationsymbol 2702 and learns, from the data 3001 about “supported schemes”,that the terminal #p supports “communication scheme #A” and“communication scheme #B”.

The signal processor 155 of the base station learns, from the data 2901about “support/not support reception for multiple streams” in FIG. 30 ,that “if the communication partner transmits multiple modulated signalsof multiple streams in “communication scheme #B”, the terminal #psupports the reception of the modulated signals“. Also, the signalprocessor 155 of the base station learns, from the data 2901 about“support/not support reception for multiple streams” in FIG. 30 , that“if the communication partner transmits a modulated signal of a singlestream in “communication scheme #A” and “communication scheme #B”, theterminal #p supports the reception of the modulated signal“.

In addition, the signal processor 155 of the base station learns, fromthe data 3002 about “support/not support multi-carrier scheme” in FIG.30 , whether the terminal #p supports “single-carrier scheme”, supports“multi-carrier scheme such as OFDM”, or supports “both thesingle-carrier scheme and the multi-carrier scheme such as OFDM”.

Also, the signal processor 155 of the base station learns, from the data2801 about “support/not support demodulation of modulated signal withphase change” in FIG. 30 , whether the terminal #p supports phasechange.

At this time, the data 2801 about “support/not support demodulation ofmodulated signal with phase change” needs the configuration describedbelow, for example.

The data 2801 about “support/not support demodulation of modulatedsignal with phase change” is made up of 2 bits, and the 2 bits arerepresented by k0 and k1.

When the communication partner transmits multiple modulated signals ofmultiple streams in the single-carrier scheme of “communication scheme#B” and performs phase change at that time, in a case where the terminal#p supports the demodulation of the modulated signals, the terminal #psets k0=1. In a case where the terminal #p does not support thedemodulation, the terminal #p sets k0=0.

When the communication partner transmits multiple modulated signals ofmultiple streams in the multi-carrier scheme such as OFDM of“communication scheme #B” and performs phase change at that time, in acase where the terminal #p supports the demodulation of the modulatedsignals, the terminal #p sets k1=1. In a case where the terminal #p doesnot support the demodulation, the terminal #p sets k1=0.

The signal processor 155 of the base station learns, from the data 3003about “supported error-correcting coding schemes” in FIG. 30 , that theterminal #p supports the decoding of “error-correcting coding scheme#C”′ and “error-correcting coding scheme #D”.

Thus, the base station (AP) appropriately generates and transmits amodulated signal that can be received by the terminal #p inconsideration of a communication scheme supported by the terminal #p anda communication environment, and accordingly the data transmissionefficiency in the system constituted by the base station (AP) and theterminal #p can be increased.

As described above, the base station (AP) obtains, from the terminal #pas a communication partner, information about a scheme in which theterminal #p supports demodulation, and decides the number of modulatedsignals, the communication method for the modulated signals, the signalprocessing method for the modulated signals, and so forth on the basisof the information, thereby being able to appropriately generate andtransmit a modulated signal that can be received by the terminal #p.Accordingly, the data transmission efficiency in the system constitutedby the base station (AP) and the terminal #p can be increased.

At this time, for example, when the reception capability notificationsymbol is made up of multiple pieces of data as in FIG. 30 , the basestation (AP) is able to easily determine whether the data included inthe reception capability notification symbol is valid or invalid.Accordingly, there is an advantage of being able to quickly determinethe scheme of modulated signals to be transmitted, the signal processingmethod, and so forth.

The base station (AP) transmits modulated signals to individualterminals #p by using a preferable transmission method on the basis ofthe details of information of the reception capability notificationsymbols transmitted by the individual terminals #p. Accordingly, thedata transmission efficiency is increased.

The method for configuring the data of the reception capabilitynotification symbol described in the present embodiment is an example,and the method for configuring the data of the reception capabilitynotification symbol is not limited thereto. In addition, thetransmission procedure and transmission timing for transmitting thereception capability notification symbol to the base station (AP) by theterminal #p according to the present embodiment are merely an example,and the transmission procedure and transmission timing are not limitedthereto.

The reception capability notification symbol as described above istransmitted by each terminal. However, there may be a terminal that doesnot transmit the reception capability notification symbol. The basestation (AP) receives the reception capability notification symbolstransmitted by the individual terminals and generates modulated signalsto be transmitted to the individual terminals. In particular, the basestation (AP) described in this specification transmits the modulatedsignals to the individual terminals at identical frequencies (or using acertain frequency in common) and at identical times (or using a certaintime in common). Accordingly, the data transmission efficiency in thesystem constituted by the base station (AP) and the terminals can beincreased.

Sixth Embodiment

The configuration in FIG. 26 has been described as an example of theconfiguration of the signal processor 206 in FIG. 2 in embodiments suchas the first embodiment, the second embodiment, and the thirdembodiment. Hereinafter, a description will be given of an example ofthe operations of the phase changers 305A and 305B in FIG. 26 .

As described in the third embodiment, the phase change value in thephase changer 305A is represented by Yp(i) and the phase change value inthe phase changer 305B is represented by yp(i).

At this time, zp1(i) and zp2(i) are expressed by Expression (42). Theperiod of phase change in the phase changer 305A is N, and the period ofphase change in the phase changer 305B is N. However, it is assumed thatN is an integer equal to or greater than 3, that is, an integer greaterthan 2, which is the number of streams to be transmitted or the numberof modulated signals to be transmitted. At this time, the phase changevalue Yp(i) and the phase change value yp(i) are given as in thefollowing Expression (43) and Expression (44), respectively.

$\begin{matrix}{{{Yp}(i)} = e^{j({\frac{\pi \times i}{N} + \Delta})}} & {{Expression}(43)}\end{matrix}$ $\begin{matrix}{{{yp}(i)} = e^{j({\frac{{- \pi} \times i}{N} + \Omega})}} & {{Expression}(44)}\end{matrix}$

Here, Δ in Expression (43) and Ω in Expression (44) are real numbers. Asan example, Δ and Ω are zero. However, Δ and Ω are not limited thereto.With such settings, the peak-to-average power ratio (PAPR) of the signalzp1(t) (or zp1(i)) and the PAPR of the signal zp2(t) (or zp2(i)) in FIG.26 are equivalent to each other in the single-carrier scheme.Accordingly, the phase noise and the request criterion for linearity ofa transmission power amplifier are equivalent among the radio sections106_1 to 106_N in FIG. 1 and so forth, which is advantageous in that lowpower consumption can be easily realized and that a common configurationcan be used for the radio sections. Also, there is a high possibilitythat a similar effect can be obtained also in the multi-carrier schemesuch as OFDM.

Alternatively, the phase change values Yp(i) and yp(i) may be given asin the following Expression (45) and Expression (46), respectively.

$\begin{matrix}{{Y{p(i)}} = e^{j({\frac{{- \pi} \times i}{N} + \Delta})}} & {{Expression}(45)}\end{matrix}$ $\begin{matrix}{{{yp}(i)} = e^{j({\frac{\pi \times i}{N} + \Omega})}} & {{Expression}(46)}\end{matrix}$

Also with Expression (45) and Expression (46), an effect similar to thatdescribed above can be obtained.

Alternatively, the phase change values Yp(i) and yp(i) may be given asin the following Expression (47) and Expression (48), respectively.

$\begin{matrix}{{Y{p(i)}} = e^{j({\frac{k \times \pi \times i}{N} + \Delta})}} & {{Expression}(47)}\end{matrix}$ $\begin{matrix}{{{yp}(i)} = e^{j({\frac{{- k} \times \pi \times i}{N} + \Omega})}} & {{Expression}(48)}\end{matrix}$

Here, k is an integer except 0. For example, k may be 1, −1, 2, or −2.The value of k is not limited thereto. Also with Expression (47) andExpression (48), an effect similar to that described above can beobtained.

Seventh Embodiment

In embodiments such as the first embodiment, the second embodiment, andthe third embodiment, examples of the configuration of the signalprocessor 206 in FIG. 2 have been described. Hereinafter, an example ofthe configuration of the signal processor 206 in FIG. 2 different fromthe examples in FIGS. 3, 4, and 26 will be described. FIG. 38 is adiagram illustrating still another example of the configuration of thesignal processor 206 in FIG. 2 . In FIG. 38 , the elements that operatesimilarly to those in FIG. 3 are denoted by the same numerals, and thedescription thereof is omitted.

A phase changer 3801B receives the user #p mapped signal 301Brepresented by sp2(t) and the control signal 300. On the basis of thecontrol signal 300, the phase changer 3801B performs phase change on theuser #p mapped signal 301B, and outputs a phase-changed signal 3802B tothe weight combiner 303.

When the weight combined signal 304A (for user #p), which is an outputof the weight combiner 303, is represented by zp1(i) and the weightcombined signal 304B (for user #p), which is an output of the weightcombiner 303, is represented by zp2(i), zp1(i) and zp2(i) are expressedby the following Expression (49).

$\begin{matrix}\begin{matrix}{\begin{pmatrix}{{zp}1(i)} \\{{zp}2(i)}\end{pmatrix} = {\begin{pmatrix}a & b \\c & d\end{pmatrix}\begin{pmatrix}1 & 0 \\0 & {{vp}(i)}\end{pmatrix}\begin{pmatrix}{{sp}1(i)} \\{{sp}2(i)}\end{pmatrix}}} \\{= {\begin{pmatrix}a & b \\c & d\end{pmatrix}\begin{pmatrix}1 & 0 \\0 & e^{j \times \delta{p(i)}}\end{pmatrix}\begin{pmatrix}{{sp}1(i)} \\{{sp}2(i)}\end{pmatrix}}}\end{matrix} & {{Expression}(49)}\end{matrix}$

Here, a, b, c, and d are defined as complex numbers, and thus may bereal numbers. Also, i is a symbol number. Here, j is the imaginary unit,and δp(i) is a real number. In addition, zp1(i) and zp2(i) aretransmitted from the transmission apparatus at identical times andidentical frequencies (identical frequency bands).

For example, a phase change value vp(i) in the phase changer 3801B isset as in the following Expression (50).

$\begin{matrix}{{{vp}(i)} = e^{j\frac{2 \times \pi \times i}{N_{p}}}} & {{Expression}(50)}\end{matrix}$

In Expression (50), j is the imaginary unit. In addition, Np is aninteger equal to or greater than 2 and represents the period of phasechange. If Np is set to an odd number equal to or greater than 3, thereis a possibility that the data reception quality is improved. Inaddition, Np may preferably be set to be greater than 2, which is thenumber of streams (the number of modulated signals) to be transmittedfor the user #p. However, Expression (50) is merely an example, and thephase change value set in the phase changer 3801B is not limitedthereto.

Next, a configuration different from those in FIGS. 3, 4, 26, and 38will be described. FIG. 39 is a diagram illustrating still anotherexample of the configuration of the signal processor 206 in FIG. 2 . InFIG. 39 , the elements that operate similarly to those in FIGS. 3 and 38are denoted by the same numerals, and the description thereof isomitted.

A phase changer 3801A receives the user #p mapped signal 301Arepresented by sp1(t) and the control signal 300. On the basis of thecontrol signal 300, the phase changer 3801A performs phase change on theuser #p mapped signal 301A, and outputs a phase-changed signal 3802A.

When the weight combined signal 304A (for user #p), which is an outputof the weight combiner 303, is represented by zp1(i) and the weightcombined signal 304B (for user #p), which is an output of the weightcombiner 303, is represented by zp2(i), zp1(i) and zp2(i) are expressedby the following Expression (51).

$\begin{matrix}\begin{matrix}{\begin{pmatrix}{{zp}1(i)} \\{{zp}2(i)}\end{pmatrix} = {\begin{pmatrix}a & b \\c & d\end{pmatrix}\begin{pmatrix}{{Vp}(i)} & 0 \\0 & {{vp}(i)}\end{pmatrix}\begin{pmatrix}{{sp}1(i)} \\{{sp}2(i)}\end{pmatrix}}} \\{= {\begin{pmatrix}a & b \\c & d\end{pmatrix}\begin{pmatrix}e^{j \times \lambda{p(i)}} & 0 \\0 & e^{j \times \delta{p(i)}}\end{pmatrix}\begin{pmatrix}{{sp}1(i)} \\{{sp}2(i)}\end{pmatrix}}}\end{matrix} & {{Expression}(51)}\end{matrix}$

Here, a, b, c, and d are defined as complex numbers, and thus may bereal numbers. Also, i is a symbol number. Here, j is the imaginary unit,and Xp(i) is a real number. In addition, zp1(i) and zp2(i) aretransmitted from the transmission apparatus at identical times (or usinga certain time in common) and identical frequencies (identical frequencybands) (or using a certain frequency in common).

By carrying out the embodiment as above, particularly in an environmentin which direct waves are dominant, when the base station transmits amodulated signal by using the above-described transmission method, aterminal as a communication partner is able to obtain high datareception quality.

Eighth Embodiment

In embodiments such as the first embodiment, the second embodiment, thethird embodiment, and the seventh embodiment, examples of theconfiguration of the signal processor 206 in FIG. 2 have been described.Hereinafter, a description will be given of an example of the operationsof the phase changers 3801A and 3801B in FIG. 39 .

As described in the seventh embodiment, the phase change value in thephase changer 3801A is represented by Vp(i), and the phase change valuein the phase changer 3801B is represented by vp(i). At this time, zp1(i)and zp2(i) are expressed by Expression (51). The period of phase changein the phase changer 3801A is N, and the period of phase change in thephase changer 3801B is N. However, it is assumed that N is an integerequal to or greater than 3, that is, an integer greater than 2, which isthe number of streams to be transmitted or the number of modulatedsignals to be transmitted. At this time, the phase change value Vp(i)and the phase change value vp(i) are given as in the followingExpression (52) and Expression (53), respectively.

$\begin{matrix}{{{Vp}(i)} = e^{j({\frac{\pi \times i}{N} + \Delta})}} & {{Expression}(52)}\end{matrix}$ $\begin{matrix}{{{vp}(i)} = e^{j({\frac{{- \pi} \times i}{N} + \Omega})}} & {{Expression}(53)}\end{matrix}$

Here, Δ in Expression (52) and Ω in Expression (53) are real numbers. Asan example, Δ and Ω are zero. However, Δ and Ω are not limited thereto.With such settings, the peak-to-average power ratio (PAPR) of the signalzp1(t) (or zp1(i)) and the PAPR of the signal zp2(t) (or zp2(i)) in FIG.39 are equivalent to each other in the single-carrier scheme.Accordingly, the phase noise and the request criterion for linearity ofa transmission power amplifier are equivalent among the radio sections106_1 to 106_N in FIG. 1 and so forth, which is advantageous in that lowpower consumption can be easily realized and that a common configurationcan be used for the radio sections. Also, there is a high possibilitythat a similar effect can be obtained also in the multi-carrier schemesuch as OFDM.

Alternatively, the phase change values Vp(i) and vp(i) may be given asin the following Expression (54) and Expression (55), respectively.

$\begin{matrix}{{{Vp}(i)} = e^{j({\frac{{- \pi} \times i}{N} + \Delta})}} & {{Expression}(54)}\end{matrix}$ $\begin{matrix}{{{vp}(i)} = e^{j({\frac{\pi \times i}{N} + \Omega})}} & {{Expression}(55)}\end{matrix}$

Also with Expression (54) and Expression (55), an effect similar to thatdescribed above can be obtained.

Alternatively, the phase change values Vp(i) and vp(i) may be given asin the following Expression (56) and Expression (57), respectively.

$\begin{matrix}{{{Vp}(i)} = e^{j({\frac{k \times \pi \times i}{N} + \Delta})}} & {{Expression}(56)}\end{matrix}$ $\begin{matrix}{{{vp}(i)} = e^{j({\frac{{- k} \times \pi \times i}{N} + \Omega})}} & {{Expression}(57)}\end{matrix}$

Here, k is an integer except 0. For example, k may be 1, −1, 2, or −2.The value of k is not limited thereto. Also with Expression (56) andExpression (57), an effect similar to that described above can beobtained.

Ninth Embodiment

In the present embodiment, the arrangement of phase changers will bedescribed. In FIGS. 3 and 26 described above, a configuration in whichphase changers are arranged on the output side of the weight combiner303 (hereinafter referred to as downstream of the weight combiner 303 asappropriate) is illustrated. In FIGS. 38 and 39 , a configuration inwhich phase changers are arranged on the input side of the weightcombiner 303 (hereinafter referred to as upstream of the weight combiner303 as appropriate) is illustrated. The phase changers may be arrangedboth upstream and downstream of the weight combiner 303. In the presentembodiment, a description will be given of an example in which phasechanges are arranged upstream and downstream of the weight combiner 303.

FIG. 40 is a diagram illustrating a first example in which phasechangers are arranged upstream and downstream of the weight combiner303. In FIG. 40 , the elements similar to those in FIGS. 3, 26, 38, and39 are denoted by the same numerals, and the description thereof isomitted.

As illustrated in FIG. 40 , the phase changer 3801A is arranged upstreamof the weight combiner 303, on the side where the user #p mapped signal301A of sp1(t) is input (i.e., the upper stage on the page). The phasechanger 3801B is arranged upstream of the weight combiner 303, on theside where the user #p mapped signal 301B of sp2(t) is input (i.e., thelower stage). The phase changer 305A is arranged downstream of theweight combiner 303, on the side where the user #p weighted signal 304Ais output (i.e., the upper stage). The phase changer 305B is arrangeddownstream of the weight combiner 303, on the side where the user #pweighted signal 304B is output (i.e., the lower stage).

As illustrated in FIG. 40 , the phase changer 3801A receives the user #pmapped signal 301A of sp1(t) and the control signal 300. On the basis ofinformation about a phase change method included in the control signal300, for example, the phase changer 3801A performs phase change on theuser #p mapped signal 301A, and outputs the phase-changed signal 3802A.

Likewise, the phase changer 3801B receives the user #p mapped signal301B of sp2(t) and the control signal 300. On the basis of informationabout a phase change method included in the control signal 300, forexample, the phase changer 3801B performs phase change on the user #pmapped signal 301B, and outputs the phase-changed signal 3802B.

The phase-changed signal 306A is input to the inserter 307A illustratedin FIGS. 3, 26, 38, and 39 , and the phase-changed signal 306B is inputto the inserter 307B illustrated in FIGS. 3, 26, 38, and 39 .

FIG. 41 is a diagram illustrating a second example in which phasechangers are arranged upstream and downstream of the weight combiner303. In FIG. 41 , the elements similar to those in FIGS. 3, 26, 38, 39,and 40 are denoted by the same numerals, and the description thereof isomitted.

In FIG. 41 , unlike in FIG. 40 , only the phase changer 305B is arrangeddownstream of the weight combiner 303. The weighted signal 304A is inputto the inserter 307A illustrated in FIGS. 3, 26, 38, and 39 . Also, thephase-changed signal 306B is input to the inserter 307B illustrated inFIGS. 3, 26, 38, and 39 .

FIG. 42 is a diagram illustrating a third example in which phasechangers are arranged upstream and downstream of the weight combiner303. In FIG. 42 , the elements similar to those in FIGS. 3, 26, 38, 39,and 40 are denoted by the same numerals, and the description thereof isomitted.

In FIG. 42 , unlike in FIG. 41 , the phase changer 305A existsdownstream of the weight combiner 303 in the upper stage. Thephase-changed signal 306A is input to the inserter 307A illustrated inFIGS. 3, 26, 38, and 39 . Also, the weighted signal 304B is input to theinserter 307B illustrated in FIGS. 3, 26, 38, and 39 .

FIG. 43 is a diagram illustrating a fourth example in which phasechangers are arranged upstream and downstream of the weight combiner303. In FIG. 43 , the elements similar to those in FIGS. 3, 26, 38, 39,and 40 are denoted by the same numerals, and the description thereof isomitted.

In FIG. 43 , unlike in FIG. 40 , only the phase changer 3801B existsupstream of the weight combiner 303. The phase-changed signal 306A isinput to the inserter 307A illustrated in FIGS. 3, 26, 38, and 39 .Also, the phase-changed signal 306B is input to the inserter 307Billustrated in FIGS. 3, 26, 38, and 39 .

FIG. 44 is a diagram illustrating a fifth example in which phasechangers are arranged upstream and downstream of the weight combiner303. In FIG. 44 , the elements similar to those in FIGS. 3, 26, 38, 39,and 40 are denoted by the same numerals, and the description thereof isomitted.

In FIG. 44 , unlike in FIG. 43 , the phase changer 3801A exists upstreamof the weight combiner 303 in the upper stage. The phase-changed signal306A is input to the inserter 307A illustrated in FIGS. 3, 26, 38, and39 . Also, the phase-changed signal 306B is input to the inserter 307Billustrated in FIGS. 3, 26, 38, and 39 .

FIG. 45 is a diagram illustrating a sixth example in which phasechangers are arranged upstream and downstream of the weight combiner303. In FIG. 45 , the elements similar to those in FIGS. 3, 26, 38, 39,and 40 are denoted by the same numerals, and the description thereof isomitted.

In FIG. 45 , the phase changer 3801B is arranged upstream of the weightcombiner 303 in the lower stage, and the phase changer 305B is arrangeddownstream of the weight combiner 303 in the lower stage. The weightedsignal 304A is input to the inserter 307A illustrated in FIGS. 3, 26,38, and 39 . Also, the phase-changed signal 306B is input to theinserter 307B illustrated in FIGS. 3, 26, 38, and 39 .

FIG. 46 is a diagram illustrating a seventh example in which phasechangers are arranged upstream and downstream of the weight combiner303. In FIG. 46 , the elements similar to those in FIGS. 3, 26, 38, 39,and 40 are denoted by the same numerals, and the description thereof isomitted.

In FIG. 46 , the phase changer 3801B is arranged upstream of the weightcombiner 303 in the lower stage, and the phase changer 305A is arrangeddownstream of the weight combiner 303 in the upper stage. Thephase-changed signal 306A is input to the inserter 307A illustrated inFIGS. 3, 26, 38, and 39 . Also, the weighted signal 304B is input to theinserter 307B illustrated in FIGS. 3, 26, 38, and 39 .

FIG. 47 is a diagram illustrating an eighth example in which phasechangers are arranged upstream and downstream of the weight combiner303. In FIG. 47 , the elements similar to those in FIGS. 3, 26, 38, 39,and 40 are denoted by the same numerals, and the description thereof isomitted.

In FIG. 47 , the phase changer 3801A is arranged upstream of the weightcombiner 303 in the upper stage, and the phase changer 305B is arrangeddownstream of the weight combiner 303 in the lower stage. The weightedsignal 304A is input to the inserter 307A illustrated in FIGS. 3, 26,38, and 39 . Also, the phase-changed signal 306B is input to theinserter 307B illustrated in FIGS. 3, 26, 38, and 39 .

FIG. 48 is a diagram illustrating a ninth example in which phasechangers are arranged upstream and downstream of the weight combiner303. In FIG. 48 , the elements similar to those in FIGS. 3, 26, 38, 39,and 40 are denoted by the same numerals, and the description thereof isomitted.

In FIG. 48 , the phase changer 3801A is arranged upstream of the weightcombiner 303 in the upper stage, and the phase changer 305A is arrangeddownstream of the weight combiner 303 in the upper stage. Thephase-changed signal 306A is input to the inserter 307A illustrated inFIGS. 3, 26, 38, and 39 . Also, the weighted signal 304B is input to theinserter 307B illustrated in FIGS. 3, 26, 38, and 39 .

Also with the above-described configurations, individual embodiments inthis specification can be carried out, and the effects described in theindividual embodiments can be obtained. The phase change methods for thephase changers 3801A, 3801B, 305A, and 305B in FIGS. 40, 41, 42, 43, 44,45, 46, 47, and 48 are set by the control signal 300, for example.

Tenth Embodiment

FIGS. 3, 26, 38, and 39 illustrate a configuration including the phasechanger 309B as the configuration after the inserter 307A (i.e., on theoutput side of the inserter 307A) and after the inserter 307B (i.e., onthe output side of the inserter 307B). In the present embodiment, adescription will be given of an example configuration different fromthis configuration. The configurations illustrated in FIGS. 40 to 48 maybe used as the configuration before the inserter 307A and before theinserter 307B.

FIG. 49 is a diagram illustrating a first example configuration on theoutput side of the inserter. In FIG. 49 , the elements similar to thosein FIGS. 3, 26, 38, 39 , and so forth are denoted by the same numerals,and the description thereof is omitted.

A Cyclic Delay Diversity (CDD) section 4909A receives the basebandsignal 308A and the control signal 300. On the basis of the controlsignal 300, the CDD section 4909A performs CDD processing on thebaseband signal 308A, and outputs a CDD-processed baseband signal 4910A.CDD may also be called Cyclic Shift Diversity (CSD).

The CDD-processed baseband signal 4910A in FIG. 49 corresponds to thesignal denoted by 207_A in FIG. 2 , and the baseband signal 308Bcorresponds to the signal denoted by 207_B in FIG. 2 .

FIG. 50 is a diagram illustrating a second example configuration on theoutput side of the inserter. In FIG. 50 , the elements similar to thosein FIGS. 3, 26, 38, 39 , and so forth are denoted by the same numerals,and the description thereof is omitted.

A CDD section 4909B receives the baseband signal 308B and the controlsignal 300. On the basis of the control signal 300, the CDD section4909B performs CDD processing on the baseband signal 308B, and outputs aCDD-processed baseband signal 4910B.

The baseband signal 308A in FIG. 50 corresponds to the signal denoted by207_A in FIG. 2 , and the CDD-processed baseband signal 4910Bcorresponds to the signal denoted by 207_B in FIG. 2 .

FIG. 51 is a diagram illustrating a third example configuration on theoutput side of the inserter. In FIG. 51 , the elements similar to thosein FIGS. 3, 26, 38, 39, 49, and 50 are denoted by the same numerals, andthe description thereof is omitted. The example configurationillustrated in FIG. 51 is an example configuration in which both the CDDsection 4909A illustrated in FIG. 49 and the CDD section 4909Billustrated in FIG. 50 are arranged.

The CDD-processed baseband signal 4910A in FIG. 51 corresponds to thesignal denoted by 207_A in FIG. 2 , and the CDD-processed basebandsignal 4910B corresponds to the signal denoted by 207_B in FIG. 2 .

FIGS. 49, 50, and 51 illustrate example configurations in which the CDDsection is arranged on the output side of the inserter. Alternatively, aphase changer may be arranged on the output side of the inserter, asillustrated in FIGS. 3, 26, and 38 . The position of the phase changermay be different from that in FIGS. 3, 26, and 38 . Hereinafter, thearrangement of a phase changer will be described.

FIG. 52 is a diagram illustrating a fourth example configuration on theoutput side of the inserter. In FIG. 52 , the elements similar to thosein FIGS. 3, 26, 38, 39 , and so forth are denoted by the same numerals,and the description thereof is omitted.

A phase changer 309A receives the baseband signal 308A and the controlsignal 300. On the basis of the control signal 300, the phase changer309A performs phase change processing on the baseband signal 308A, andoutputs a phase-changed baseband signal 310A.

The phase-changed baseband signal 310A in FIG. 52 corresponds to thesignal denoted by 207_A in FIG. 2 , and the baseband signal 308Bcorresponds to the signal denoted by 207_B in FIG. 2 .

FIG. 53 is a diagram illustrating a fifth example configuration on theoutput side of the inserter. In FIG. 53 , the elements similar to thosein FIGS. 3, 26, 38, 39, 52 , and so forth are denoted by the samenumerals, and the description thereof is omitted.

The phase-changed baseband signal 310A in FIG. 53 corresponds to thesignal denoted by 207_A in FIG. 2 , and the phase-changed basebandsignal 310B corresponds to the signal denoted by 207_B in FIG. 2 .

FIG. 54 is a diagram illustrating a sixth example configuration on theoutput side of the inserter. In FIG. 54 , the elements similar to thosein FIGS. 3, 26, 38, 39, 52 , and so forth are denoted by the samenumerals, and the description thereof is omitted.

The baseband signal 308A in FIG. 54 corresponds to the signal denoted by207_A in FIG. 2 , and the baseband signal 308B corresponds to the signaldenoted by 207_B in FIG. 2 .

Also with the above-described configurations, individual embodiments inthis specification can be carried out, and the effects described in theindividual embodiments can be obtained.

Regarding CDD (CSD)

In the first embodiment, the ninth embodiment, and so forth, CDD (CSD)is described. In FIGS. 49, 50, and 51 , the CDD sections 4909A and 4909Bare illustrated. In addition, in FIGS. 3, 26, 38, 39, 52, 53, and 54 ,the phase changers 309A and 309B are illustrated.

Hereinafter, a supplemental description will be given of specificprocessing of CDD (CSD) and phase change.

FIG. 55 is a diagram for describing CDD (CSD). In FIGS. 55 , 5502_1 to5502_M denote the sections that perform processing similar to theprocessing performed by the CDD sections 4909A and 4909B in FIGS. 49,50, and 51 . In FIG. 55 , a modulated signal 5501 that is to besubjected to cyclic delay is represented by X[n]. It is assumed thatX[n] is made up of N samples (N is an integer equal to or greater than2), and thus n is an integer from 0 to N-1.

The cyclic delay section 5502_1 receives the modulated signal 5501,performs cyclic delay processing, and outputs a cyclic-delay-processedsignal 5503_1. When the cyclic-delay-processed signal 5503_1 isrepresented by X1[n], X1[n] is given as the following Expression (58).

X1[n]=X[(n−δ1)mod N]  Expression (58)

Here, δ1 is a cyclic delay amount (δ1 is a real number). In addition,mod represents modulo, and “A mod B” means “a remainder obtained bydividing A by B”. That is, X1[n] is a signal obtained by delaying themodulated signal X[n] having N samples by 61 and moving the portion inthe range from (N−δ1) to N of the modulated signal X[n] to the top. Inthe description given above, a discrete signal is described as anexample, but similar processing may be performed on a continuous signal.The same applies to an output signal of cyclic delay in the followingdescription.

The cyclic delay section 5502_M receives the modulated signal 5501,performs cyclic delay processing, and outputs a cyclic-delay-processedsignal 5503_M. When the cyclic-delay-processed signal 5503_M isrepresented by XM[n], XM[n] is given as the following Expression (59).

XM[n]=X[(n−δM)mod N]  Expression (59)

Here, δM is a cyclic delay amount (δM is an integer).

Thus, a cyclic delay section 5502_i (i is in integer from 1 to M (M isan integer equal to or greater than 1) receives the modulated signal5501, performs cyclic delay processing, and outputs acyclic-delay-processed signal 5503_i. When the cyclic-delay-processedsignal 5503_i is represented by Xi[n], Xi[n] is given as the followingExpression (60).

Xi[n]=X[(n−δi)mod N]  Expression (60)

Here, δi is an amount of cyclic delay (δi is an integer).

The cyclic-delay-processed signal 5503_i is transmitted from an antennai (thus, the cyclic-delay-processed signal 5503_1, . . . , and thecyclic-delay-processed signal 5503_M are transmitted from differentantennas).

Accordingly, a diversity effect of cyclic delay can be obtained (inparticular, a negative influence of a delayed wave can be reduced), andthe data reception quality can be improved in the reception apparatus.

For example, the phase changers 309A and 309B in FIGS. 3, 26, 38, 39,52, 53 , and 54 may be replaced with the cyclic delay sectionsillustrated in FIG. 55 , and the operations of the phase changers 309Aand 309B may be the same as the operations of the cyclic delay sections.

Thus, a cyclic delay amount δ (δ is an integer) is given in the phasechangers 309A and 309B in FIGS. 3, 26, 38, 39, 52, 53, and 54 , and theinput signal of the phase changers 309A and 309B is represented by Y[n].When the output signal of the phase changer 209B is represented by Z[n],Z[n] is given as Expression (61).

Z[n]=Y[(n−δ)mod N]  Expression (61)

Here, Y[n] is made up of N symbols (N is an integer equal to or greaterthan 2). Thus, n is an integer from 0 to N-1.

Next, a description will be given of the relationship between a cyclicdelay amount and phase change. For example, the case of applying CDD(CSD) to OFDM will be discussed. It is assumed that the carrier of thelowest frequency is “carrier 1”, and “carrier 2”, “carrier 3”, and“carrier 4” follow in this order.

For example, it is assumed that a cyclic delay amount μ is given in thephase changers 309A and 309B in FIGS. 3, 26, 38, 39, 52, 53, and 54 .Then, a phase change value Ω[i] in “carrier i” is expressed by thefollowing Expression (62).

Ω[i]=e ^(j×μ×i)  Expression (62)

Here, μ is a value that can be obtained from a cyclic delay amount, afast Fourier transform (FFT) size, and so forth.

When “carrier i” before phase change (before cyclic delay processing)and the baseband signal at time t are represented by v′[i][t], “carrieri” after phase change and the signal v[i][t] at time t can be expressedby v[i][t]=Ω[i]×v′[i][t].

Eleventh Embodiment

In this specification, the example configuration illustrated in FIG. 2has been described as an example of the configuration of the user #psignal processor 102_p in FIG. 1 . In the present embodiment, adescription will be given of a configuration different from that in FIG.2 as the configuration of the user #p signal processor 102_p in FIG. 1 .

FIG. 56 is a diagram illustrating an example of the configuration of theuser #p signal processor different from that in FIG. 2 . In FIG. 56 ,the elements similar to those in FIG. 2 are denoted by the samereference numerals, and the description thereof is omitted. In FIG. 56 ,the point different from FIG. 2 is that multiple error-correctingencoders and multiple mappers exist.

Specifically, in FIG. 56 , two error-correcting encoders(error-correcting encoders 202_1 and 202_2) exist. FIG. 2 illustrates aconfiguration including one error-correcting encoder 202 and FIG. 56illustrates a configuration including two error-correcting encoders(202_1 and 202_2), but the number of error-correcting encoders is notlimited thereto. For example, in a case where there are three or moreerror-correcting encoders, the mapper 204 (204_1 and 204_2) performsmapping by using the data output from each error-correcting encoder.

In FIG. 56 , the error-correcting encoder 202_1 receives first data201_1 and the control signal 200. On the basis of information about anerror-correcting coding method included in the control signal 200, theerror-correcting encoder 202_1 performs error-correcting coding on thefirst data 201_1, and outputs coded data 203_1.

The mapper 204_1 receives the coded data 203_1 and the control signal200. On the basis of information about a modulation scheme included inthe control signal 200, the mapper 204_1 performs mapping on the codeddata 203_1, and outputs the mapped signal 205_1.

The error-correcting encoder 202_2 receives second data 201_2 and thecontrol signal 200. On the basis of information about anerror-correcting coding method included in the control signal 200, theerror-correcting encoder 202_2 performs error-correcting coding on thesecond data 201_2, and outputs coded data 203_2.

The mapper 204_2 receives the coded data 203_2 and the control signal200. On the basis of information about a modulation scheme included inthe control signal 200, the mapper 204_2 performs mapping on the codeddata 203_2, and outputs the mapped signal 205_2.

In the each embodiment described in this specification, even if theconfiguration of the user #p signal processor 102_p illustrated in FIG.2 is replaced with the configuration illustrated in FIG. 56 , theembodiment can be carried out similarly and a similar effect can beobtained.

In addition, for example, the case of generating a signal with theconfiguration in FIG. 2 and the case of generating a signal with theconfiguration in FIG. 56 may be switched in the user #p signal processor102_p.

Twelfth Embodiment

In the above embodiments, a description has been given of theconfigurations in which a mapper is included in the user #p signalprocessor, with reference to FIGS. 2, 31, 32, and 56 , for example. Inthe present embodiment, a description will be given of a method forrealizing robust communication in the mapper, by using the followingfirst to sixth examples.

First Example

FIG. 57 is a diagram illustrating the first example of the operation ofa mapper 5702. The operation of the mapper 5702 illustrated in FIG. 57corresponds to an example of the operation of the mapper 204 in the user#p signal processor 102_p illustrated in FIG. 2 . In addition, a controlsignal 5700 corresponds to the control signal 200 in FIG. 2 , coded data5701 corresponds to the user #p data 203 in FIG. 2 , a mapped signal5703A corresponds to the mapped signal 205_1 in FIG. 2 , and a mappedsignal 5703B corresponds to the mapped signal 205_2 in FIG. 2 .

The mapper 5702 receives the coded data 5701 and the control signal5700. In a case where a robust transmission method is designated by thecontrol signal 5700, the mapper 5702 performs the mapping describedbelow, and outputs the mapped signals 5703A and 5703B (for the user #p).

It is assumed that bit c0(k), bit c1(k), bit c2(k), and bit c3(k) areinput as the coded data 5701 to the mapper 5702. Here, k is an integerequal to or greater than 0.

It is assumed that the mapper 5702 performs QPSK modulation on c0(k) andc1(k) to obtain a mapped signal a(k). In addition, it is assumed thatthe mapper 5702 performs QPSK modulation on c2(k) and c3(k) to obtain amapped signal b(k).

Also, it is assumed that the mapper 5702 performs QPSK modulation onc0(k) and c1(k) to obtain a mapped signal a′(k). In addition, it isassumed that the mapper 5702 performs QPSK modulation on c2(k) and c3(k)to obtain a mapped signal b′(k).

The mapped signal 5703A with a symbol number i=2k is represented bysp1(i=2k), and the mapped signal 5703B with a symbol number i=2k isrepresented by sp2(i=2k). Also, the mapped signal 5703A with a symbolnumber i=2k+1 is represented by sp1(i=2k+1), and the mapped signal 5703Bwith a symbol number i=2k+1 is represented by sp2(i=2k+1).

In addition, sp1(i=2k), which is the mapped signal 5703A with a symbolnumber i=2k, is represented by a(k), and sp2(i=2k), which is the mappedsignal 5703B with a symbol number i=2k, is represented by b(k). Also,sp1(i=2k+1), which is the mapped signal 5703A with a symbol numberi=2k+1, is represented by b′(k), and sp2(i=2k+1), which is the mappedsignal 5703B with a symbol number i=2k+1, is represented by a′(k).

That is, the mapper 5702 performs QPSK modulation on c0(k) and c1(k) togenerate a(k) as the mapped signal 5703A (sp1(i=2k)) with a symbolnumber i=2k. Also, the mapper 5702 performs QPSK modulation on c0(k) andc1(k) to generate a′(k) as the mapped signal 5703B (sp2(i=2k+1)) with asymbol number i=2k+1.

Also, the mapper 5702 performs QPSK modulation on c2(k) and c3(k) togenerate b(k) as the mapped signal 5703B (sp2(i=2k)) with a symbolnumber i=2k. Also, the mapper 5702 performs QPSK modulation on c2(k) andc3(k) to generate b′(k) as the mapped signal 5703A (sp1(i=2k+1)) with asymbol number i=2k+1.

In this way, the mapper 5702 outputs two mapped signals (for example,a(k) and a′(k)) with different symbol numbers i and different streams(i.e., sp1 or sp2) by using identical bits (for example, c0(k) andc1(k)).

As described above, a(k) and a′(k) are generated from the identical bitsc0(k) and c1(k) and output from the mapper 5702 as different symbolnumbers and different streams. Likewise, b(k) and b′(k) are generatedfrom the identical bits c2(k) and c3(k) and output from the mapper 5702as different symbol numbers and different streams.

The mapper 5702 may change signal point arrangement when generating a(k)and a′(k). Also, the mapper 5702 may change signal point arrangementwhen generating b(k) and b′(k). Hereinafter, a description will be givenof an example of signal point arrangement of QPSK modulation, an exampleof the relationship between a(k) and a′(k), and an example of therelationship between b(k) and b′(k).

Example of Signal Point Arrangement of QPSK Modulation

FIG. 58 is a diagram illustrating a first example of signal pointarrangement of QPSK modulation on the in-phase I quadrature Q plane.FIG. 58 illustrates the relationship among signal points for the valuesof bit x0 and bit x1.

When bit [x0, x1]=[0, 0] (x0 is 0, x1 is 0), an in-phase component I=zand a quadrature component Q=z are set. This is a signal point 5801.Here, z is a real number greater than 0. When bit [x0, x1]=[0, 1] (x0 is0, x1 is 1), an in-phase component I=−z and a quadrature component Q=zare set. This is a signal point 5802. When bit [x0, x1]=[1, 0] (x0 is 1,x1 is 0), an in-phase component I=z and a quadrature component Q=−z areset. This is a signal point 5803. When bit [x0, x1]=[1, 1] (x0 is 1, x1is 1), an in-phase component I=−z and a quadrature component Q=−z areset. This is a signal point 5804.

FIG. 59 is a diagram illustrating a second example of signal pointarrangement of QPSK modulation on the in-phase I quadrature Q plane.FIG. 59 illustrates the relationship among signal points for the valuesof bit x0 and bit x1. Note that the relationship of signal points withrespect to the values of bit x0 and bit x1 in FIG. 58 is different fromthe relationship of signal points with respect to the values of bit x0and bit x1 in FIG. 59 .

When bit [x0, x1]=[0, 0] (x0 is 0, x1 is 0), an in-phase component I=zand a quadrature component Q=−z are set. This is a signal point 5903.Here, z is a real number greater than 0. When bit [x0, x1]=[0, 1] (x0 is0, x1 is 1), an in-phase component I=−z and a quadrature component Q=−zare set. This is a signal point 5904. When bit [x0, x1]=[1, 0] (x0 is 1,x1 is 0), an in-phase component I=z and a quadrature component Q=z areset. This is a signal point 5901. When bit [x0, x1]=[1, 1] (x0 is 1, x1is 1), an in-phase component I=−z and a quadrature component Q=z areset. This is a signal point 5902.

FIG. 60 is a diagram illustrating a third example of signal pointarrangement of QPSK modulation on the in-phase I quadrature Q plane.FIG. 60 illustrates the relationship among signal points for the valuesof bit x0 and bit x1. Note that the “relationship of signal points withrespect to the values of bit x0 and bit x1” in FIG. 60 is different fromthe “relationship of signal points with respect to the values of bit x0and bit x1” in FIG. 58 and the “relationship of signal points withrespect to the values of bit x0 and bit x1” in FIG. 59 .

When bit [x0, x1]=[0, 0] (x0 is 0, x1 is 0), an in-phase component I=−zand a quadrature component Q=z are set. This is a signal point 6002.Here, z is a real number greater than 0. When bit [x0, x1]=[0, 1] (x0 is0, x1 is 1), an in-phase component I=z and a quadrature component Q=zare set. This is a signal point 6001. When bit [x0, x1]=[1, 0] (x0 is 1,x1 is 0), an in-phase component I=−z and a quadrature component Q=−z areset. This is a signal point 6004. When bit [x0, x1]=[1, 1] (x0 is 1, x1is 1), an in-phase component I=z and a quadrature component Q=−z areset. This is a signal point 6003.

FIG. 61 is a diagram illustrating a fourth example of signal pointarrangement of QPSK modulation on the in-phase I quadrature Q plane.FIG. 61 illustrates the relationship among signal points for the valuesof bit x0 and bit x1. Note that the “relationship of signal points withrespect to the values of bit x0 and bit x1” in FIG. 61 is different fromthe “relationship of signal points with respect to the values of bit x0and bit x1” in FIG. 58 , the “relationship of signal points with respectto the values of bit x0 and bit x1” in FIG. 59 , and the “relationshipof signal points with respect to the values of bit x0 and bit x1” inFIG. 60 .

When bit [x0, x1]=[0, 0] (x0 is 0, x1 is 0), an in-phase component I=−zand a quadrature component Q=−z are set. This is a signal point 6104.Here, z is a real number greater than 0. When bit [x0, x1]=[0, 1] (x0 is0, x1 is 1), an in-phase component I=z and a quadrature component Q=−zare set. This is a signal point 6103. When bit [x0, x1]=[1, 0] (x0 is 1,x1 is 0), an in-phase component I=−z and a quadrature component Q=z areset. This is a signal point 6102. When bit [x0, x1]=[1, 1] (x0 is 1, x1is 1), an in-phase component I=z and a quadrature component Q=z are set.This is a signal point 6101.

Example of Relationship Between a(k) and a′(k)

For example, it is assumed that the mapper 5702 uses the signal pointarrangement in FIG. 58 to generate a(k). In a case where c0(k)=0 andc1(k)=0, the mapper 5702 maps c0(k)=0 and c1(k)=0 to the signal point5801 on the basis of the signal point arrangement in FIG. 58 . That is,in this case, the signal point 5801 corresponds to a(k).

Settings are made so that the mapper 5702 uses any of the signal pointarrangement in FIG. 58 , the signal point arrangement in FIG. 59 , thesignal point arrangement in FIG. 60 , and the signal point arrangementin FIG. 61 to generate a′(k).

<1> In a case where settings are made so that the signal pointarrangement in FIG. 58 is used to generate a′(k), c0(k)=0 and c1(k)=0,and thus the mapper 5702 maps c0(k)=0 and c1(k)=0 to the signal point5801 on the basis of the signal point arrangement in FIG. 58 . That is,in this case, the signal point 5801 corresponds to a′(k).

<2> In a case where settings are made so that the signal pointarrangement in FIG. 59 is used to generate a′(k), c0(k)=0 and c1(k)=0,and thus the mapper 5702 maps c0(k)=0 and c1(k)=0 to the signal point5903 on the basis of the signal point arrangement in FIG. 59 . That is,in this case, the signal point 5903 corresponds to a′(k).

<3> In a case where settings are made so that the signal pointarrangement in FIG. 60 is used to generate a′(k), c0(k)=0 and c1(k)=0,and thus the mapper 5702 maps c0(k)=0 and c1(k)=0 to the signal point6002 on the basis of the signal point arrangement in FIG. 60 . That is,in this case, the signal point 6002 corresponds to a′(k).

<4> In a case where settings are made so that the signal pointarrangement in FIG. 61 is used to generate a′(k), c0(k)=0 and c1(k)=0,and thus the mapper 5702 maps c0(k)=0 and c1(k)=0 to the signal point6104 on the basis of the signal point arrangement in FIG. 61 . That is,in this case, the signal point 6104 corresponds to a′(k).

As described above, the relationship between “the bits and signal pointarrangement for generating a(k)” and the relationship between “the bitsand signal point arrangement for generating a′(k)” may be identical toor different from each other.

As an “example of a case where the relationships are identical”, adescription has been given of an example of using FIG. 58 to generatea(k) and using FIG. 58 to generate a′(k).

As an “example of a case where the relationships are different”, adescription has been given of an example of using FIG. 58 to generatea(k) and using FIG. 59 to generate a′(k), an example of using FIG. 58 togenerate a(k) and using FIG. 60 to generate a′(k), and an example ofusing FIG. 58 to generate a(k) and using FIG. 61 to generate a′(k).

For another example, the modulation scheme for generating a(k) may bedifferent from the modulation scheme for generating a′(k).Alternatively, the signal point arrangement on the in-phase I quadratureQ plane for generating a(k) may be different from the signal pointarrangement on the in-phase I quadrature Q plane for generating a′(k).

For example, QPSK may be used as described above as the modulationscheme for generating a(k), and a modulation scheme of signal pointarrangement different from QPSK may be used as the modulation scheme forgenerating a′(k). In addition, the signal point arrangement in FIG. 58may be used as the signal point arrangement on the in-phase I quadratureQ plane for generating a(k), and a signal point arrangement differentfrom that in FIG. 58 may be used as the signal point arrangement on thein-phase I quadrature Q plane for generating a′(k).

A state where the signal point arrangement on the in-phase I quadratureQ plane is different means, for example, when the coordinates of thefour signal points on the in-phase I quadrature Q plane for generatinga(k) is those in FIG. 58 , at least one of the four signal points on thein-phase I quadrature Q plane for generating a′(k) does not overlap anyof the four signal points in FIG. 58 .

Example of Relationship Between b(k) and b′(k)

For example, it is assumed that the mapper 5702 uses the signal pointarrangement in FIG. 58 to generate b(k). In a case where c2(k)=0 andc3(k)=0, the mapper 5702 maps c2(k)=0 and c3(k)=0 to the signal point5801 on the basis of the signal point arrangement in FIG. 58 . That is,in this case, the signal point 5801 corresponds to b(k).

Settings are made so that the mapper 5702 uses any of the signal pointarrangement in FIG. 58 , the signal point arrangement in FIG. 59 , thesignal point arrangement in FIG. 60 , and the signal point arrangementin FIG. 61 to generate b′(k).

<5> In a case where settings are made so that the signal pointarrangement in FIG. 58 is used to generate b′(k), c2(k)=0 and c3(k)=0,and thus the mapper 5702 maps c2(k)=0 and c3(k)=0 to the signal point5801 on the basis of the signal point arrangement in FIG. 58 . That is,in this case, the signal point 5801 corresponds to b′(k).

<6> In a case where settings are made so that the signal pointarrangement in FIG. 59 is used to generate b′(k), c2(k)=0 and c3(k)=0,and thus the mapper 5702 maps c2(k)=0 and c3(k)=0 to the signal point5903 on the basis of the signal point arrangement in FIG. 59 . That is,in this case, the signal point 5903 corresponds to b′(k).

<7> In a case where settings are made so that the signal pointarrangement in FIG. 60 is used to generate b′(k), c2(k)=0 and c3(k)=0,and thus the mapper 5702 maps c2(k)=0 and c3(k)=0 to the signal point6002 on the basis of the signal point arrangement in FIG. 60 . That is,in this case, the signal point 6002 corresponds to b′(k).

<8> In a case where settings are made so that the signal pointarrangement in FIG. 61 is used to generate b′(k), c2(k)=0 and c3(k)=0,and thus the mapper 5702 maps c2(k)=0 and c3(k)=0 to the signal point6104 on the basis of the signal point arrangement in FIG. 61 . That is,in this case, the signal point 6104 corresponds to b′(k).

As described above, the relationship between “the bits and signal pointarrangement for generating b(k)” and the relationship between “the bitsand signal point arrangement for generating b′(k)” may be identical toor different from each other.

As an “example of a case where the relationships are identical”, adescription has been given of an example of using FIG. 58 to generateb(k) and using FIG. 58 to generate b′(k).

As an “example of a case where the relationships are different”, adescription has been given of an example of using FIG. 58 to generateb(k) and using FIG. 59 to generate b′(k), an example of using FIG. 58 togenerate b(k) and using FIG. 60 to generate b′(k), and an example ofusing FIG. 58 to generate b(k) and using FIG. 61 to generate b′(k).

For another example, the modulation scheme for generating b(k) may bedifferent from the modulation scheme for generating b′(k).Alternatively, the signal point arrangement on the in-phase I quadratureQ plane for generating b(k) may be different from the signal pointarrangement on the in-phase I quadrature Q plane for generating b′(k).

For example, QPSK may be used as described above as the modulationscheme for generating b(k), and a modulation scheme of signal pointarrangement different from QPSK may be used as the modulation scheme forgenerating b′(k). In addition, the signal point arrangement in FIG. 58may be used as the signal point arrangement on the in-phase I quadratureQ plane for generating b(k), and a signal point arrangement differentfrom that in FIG. 58 may be used as the signal point arrangement on thein-phase I quadrature Q plane for generating b′(k).

A state where the signal point arrangement on the in-phase I quadratureQ plane is different means, for example, when the coordinates of thefour signal points on the in-phase I quadrature Q plane for generatingb(k) is those in FIG. 58 , at least one of the four signal points on thein-phase I quadrature Q plane for generating b′(k) does not overlap anyof the four signal points in FIG. 58 .

As described above, the mapped signal 5703A corresponds to the mappedsignal 205_1 in FIG. 2 , and the mapped signal 5703B corresponds to themapped signal 205_2 in FIG. 2 . Thus, the mapped signal 5703A and themapped signal 5703B are to be subjected to phase change, CDD processing,and weight combining processing performed as in FIGS. 3, 26, 38, 39, 40to 48, 49 to 54 , and so forth related to the signal processor 206 inFIG. 2 and so forth. However, in a case where ON/OFF of phase change ispossible, phase change may be set to OFF, that is, phase change is notperformed. In addition, in FIGS. 3, 26, 38, 39, 40 to 48, and 49 to 54 ,a configuration not including a phase changer may be adopted.

Second Example

FIG. 62 is a diagram illustrating an example of the configuration of theuser #p signal processor 102_p different from the configurations inFIGS. 2 and 56 . In FIG. 62 , the elements similar to those in FIGS. 2and 56 are denoted by the same numerals, and the description thereof isomitted. The user #p signal processor 102_p in FIG. 62 is different fromthat in FIG. 2 in that two error-correcting encoders 202_1 and 202_2 areincluded. In addition, the user #p signal processor 102_p in FIG. 62 isdifferent from that in FIG. 56 in that one mapper 204 is included.

The mapper 204 in FIG. 62 receives the coded data 203_1 and 203_2 andthe control signal 200. On the basis of information about a mappingmethod included in the control signal 200, the mapper 204 in FIG. 62performs mapping, and outputs the mapped signals 205_1 and 205_2.

FIG. 63 is a diagram illustrating the second example of the operation ofthe mapper 5702. The operation of the mapper 5702 illustrated in FIG. 63corresponds to an example of the operation of the mapper 204 illustratedin FIG. 62 . In FIG. 63 , the elements that operate similarly to thosein FIG. 57 are denoted by the same numerals, and the description thereofis omitted. In addition, the control signal 5700 corresponds to thecontrol signal 200 in FIG. 62 , coded data 6301_1 corresponds to thecoded data 203_1 in FIG. 62 , coded data 6301_2 corresponds to the codeddata 203_2 in FIG. 62 , the mapped signal 5703A corresponds to themapped signal 205_1 in FIG. 62 , and the mapped signal 5703B correspondsto the mapped signal 205_2 in FIG. 62 .

The mapper 5702 receives the coded data 6301_1 and 6301_2 and thecontrol signal 5700. In a case where a robust transmission method isdesignated by the control signal 5700, the mapper 5702 performs themapping described below, and outputs the mapped signals 5703A and 5703B.

For example, it is assumed that bit c0(k) and bit c1(k) are input as thecoded data 6301_1 to the mapper 5702, and bit c2(k) and bit c3(k) areinput as the coded data 6301_2 to the mapper 5702. Here, k is an integerequal to or greater than 0.

It is assumed that the mapper 5702 performs QPSK modulation on c0(k) andc1(k) to obtain a mapped signal a(k). In addition, it is assumed thatthe mapper 5702 performs QPSK modulation on c2(k) and c3(k) to obtain amapped signal b(k).

Also, it is assumed that the mapper 5702 performs QPSK modulation onc0(k) and c1(k) to obtain a mapped signal a′(k). In addition, it isassumed that the mapper 5702 performs QPSK modulation on c2(k) and c3(k)to obtain a mapped signal b′(k).

The mapped signal 5703A with a symbol number i=2k is represented bys1(i=2k), and the mapped signal 5703B with a symbol number i=2k isrepresented by s2(i=2k). Also, the mapped signal 5703A with a symbolnumber i=2k+1 is represented by s1(i=2k+1), and the mapped signal 5703Bwith a symbol number i=2k+1 is represented by s2(i=2k+1).

In addition, s1(i=2k), which is the mapped signal 5703A with a symbolnumber i=2k, is represented by a(k), and s2(i=2k), which is the mappedsignal 5703B with a symbol number i=2k, is represented by b(k). Also,s1(i=2k+1), which is the mapped signal 5703A with a symbol numberi=2k+1, is represented by b′(k), and s2(i=2k+1), which is the mappedsignal 5703B with a symbol number i=2k+1, is represented by a′(k).

An example of the relationship between a(k) and a′(k), and an example ofthe relationship between b(k) and b′(k) are similar to the relationshipsdescribed by using FIGS. 58, 59, 60, and 61 .

As described above, the mapped signal 5703A corresponds to the mappedsignal 205_1 in FIG. 62 , and the mapped signal 5703B corresponds to themapped signal 205_2 in FIG. 62 . Thus, the mapped signal 5703A and themapped signal 5703B are to be subjected to phase change, CDD processing,and weight combining processing performed as in FIGS. 3, 26, 38, 39, 40to 48, 49 to 54 , and so forth related to the signal processor 206 inFIG. 62 . However, in a case where ON/OFF of phase change is possible,phase change may be set to OFF, that is, phase change is not performed.In addition, in FIGS. 3, 26, 38, 39, 40 to 48 , and 49 to 54, aconfiguration not including a phase changer may be adopted.

Third Example

The third example is, like the second example, an example of theoperation of the mapper 204 in the configuration of the user #p signalprocessor 102_p illustrated in FIG. 62 , that is, the configurationincluding the two error-correcting encoders 202_1 and 202_2 and the onemapper 204.

FIG. 64 is a diagram illustrating the third example of the operation ofthe mapper 5702. The operation of the mapper 5702 illustrated in FIG. 64corresponds to an example of the operation of the mapper 204 illustratedin FIG. 62 . In FIG. 64 , the elements that operate similarly to thosein FIGS. 57 and 63 are denoted by the same numerals, and the descriptionthereof is omitted. In addition, the control signal 5700 corresponds tothe control signal 200 in FIG. 62 , the coded data 6301_1 corresponds tothe coded data 203_1 in FIG. 62 , the coded data 6301_2 corresponds tothe coded data 203_2 in FIG. 62 , the mapped signal 5703A corresponds tothe mapped signal 205_1 in FIG. 62 , and the mapped signal 5703Bcorresponds to the mapped signal 205_2 in FIG. 62 .

The mapper 5702 receives the coded data 6301_1 and 6301_2 and thecontrol signal 5700. In a case where a robust transmission method isdesignated by the control signal 5700, the mapper 5702 performs themapping described below, and outputs the mapped signals 5703A and 5703B.

For example, bit c0(k) and bit c2(k) are input as the coded data 6301_1to the mapper 5702, and bit c1(k) and bit c3(k) are input as the codeddata 6301_2 to the mapper 5702. Here, k is an integer equal to orgreater than 0.

It is assumed that the mapper 5702 performs QPSK modulation on c0(k) andc1(k) to obtain a mapped signal a(k). In addition, it is assumed thatthe mapper 5702 performs QPSK modulation on c2(k) and c3(k) to obtain amapped signal b(k). Also, it is assumed that the mapper 5702 performsQPSK modulation on c0(k) and c1(k) to obtain a mapped signal a′(k). Inaddition, it is assumed that the mapper 5702 performs QPSK modulation onc2(k) and c3(k) to obtain a mapped signal b′(k).

The mapped signal 5703A with a symbol number i=2k is represented bys1(i=2k), and the mapped signal 5703B with a symbol number i=2k isrepresented by s2(i=2k). Also, the mapped signal 5703A with a symbolnumber i=2k+1 is represented by s1(i=2k+1), and the mapped signal 5703Bwith a symbol number i=2k+1 is represented by s2(i=2k+1).

In addition, s1(i=2k), which is the mapped signal 5703A with a symbolnumber i=2k, is represented by a(k), and s2(i=2k), which is the mappedsignal 5703B with a symbol number i=2k, is represented by b(k). Also,s1(i=2k+1), which is the mapped signal 5703A with a symbol numberi=2k+1, is represented by b′(k), and s2(i=2k+1), which is the mappedsignal 5703B with a symbol number i=2k+1, is represented by a′(k).

An example of the relationship between a(k) and a′(k), and an example ofthe relationship between b(k) and b′(k) are similar to the relationshipsdescribed by using FIGS. 58, 59, 60, and 61 .

As described above, the mapped signal 5703A corresponds to the mappedsignal 205_1 in FIG. 62 , and the mapped signal 5703B corresponds to themapped signal 205_2 in FIG. 62 . Thus, the mapped signal 5703A and themapped signal 5703B are to be subjected to phase change, CDD processing,and weight combining processing performed as in FIGS. 3, 26, 38, 39, 40to 48, 49 to 54 , and so forth related to the signal processor 206 inFIG. 62 . However, in a case where ON/OFF of phase change is possible,phase change may be set to OFF, that is, phase change is not performed.In addition, in FIGS. 3, 26, 38, 39, 40 to 48 , and 49 to 54, aconfiguration not including a phase changer may be adopted.

The first to third examples given above are examples of the case ofmodulating 2-bit data. Hereinafter, fourth to sixth examples of the caseof modulating 4-bit data will be given.

Fourth Example

The fourth example is, like the first example described by using FIG. 57, an example of the operation of the mapper 204 in the configuration ofthe user #p signal processor 102_p illustrated in FIG. 2 , that is, theconfiguration including the one error-correcting encoder 202 and the onemapper 204. However, the modulation scheme used in the fourth example isdifferent from that in the first example, as described above.

FIG. 65 is a diagram illustrating the fourth example of the operation ofthe mapper 5702. The operation of the mapper 5702 illustrated in FIG. 65corresponds to an example of the operation of the mapper 204 in the user#p signal processor 102_p illustrated in FIG. 2 . The control signal5700 corresponds to the control signal 200 in FIG. 2 , the coded data5701 corresponds to the user #p data 203 in FIG. 2 , the mapped signal5703A corresponds to the mapped signal 205_1 in FIG. 2 , and the mappedsignal 5703B corresponds to the mapped signal 205_2 in FIG. 2 .

The mapper 5702 receives the coded data 5701 and the control signal5700. In a case where a robust transmission method is designated by thecontrol signal 5700, the mapper 5702 performs the mapping describedbelow, and outputs the mapped signals 5703A and 5703B.

Bit c0(k), bit c1(k), bit c2(k), bit c3(k), bit c4(k), bit c5(k), bitc6(k), and bit c7(k) are input as the coded data 5701 to the mapper5702. Here, k is an integer equal to or greater than 0.

It is assumed that the mapper 5702 performs modulation on bit c0(k), bitc1(k), bit c2(k), and bit c3(k) by using a modulation scheme havingsixteen signal points, such as 16QAM, to obtain a mapped signal a(k). Inaddition, it is assumed that the mapper 5702 performs modulation on bitc4(k), bit c5(k), bit c6(k), and bit c7(k) by using a modulation schemehaving sixteen signal points, such as 16QAM, to obtain a mapped signalb(k).

Also, it is assumed that the mapper 5702 performs modulation on bitc0(k), bit c1(k), bit c2(k), and bit c3(k) by using a modulation schemehaving sixteen signal points, such as 16QAM, to obtain a mapped signala′(k). In addition, it is assumed that the mapper 5702 performsmodulation on bit c4(k), bit c5(k), bit c6(k), and bit c7(k) by using amodulation scheme having sixteen signal points, such as 16QAM, to obtaina mapped signal b′(k).

The mapped signal 5703A with a symbol number i=2k is represented bys1(i=2k), and the mapped signal 5703B with a symbol number i=2k isrepresented by s2(i=2k). Also, the mapped signal 5703A with a symbolnumber i=2k+1 is represented by s1(i=2k+1), and the mapped signal 5703Bwith a symbol number i=2k+1 is represented by s2(i=2k+1).

In addition, s1(i=2k), which is the mapped signal 5703A with a symbolnumber i=2k, is represented by a(k), and s2(i=2k), which is the mappedsignal 5703B with a symbol number i=2k, is represented by b(k). Also,s1(i=2k+1), which is the mapped signal 5703A with a symbol numberi=2k+1, is represented by b′(k), and s2(i=2k+1), which is the mappedsignal 5703B with a symbol number i=2k+1, is represented by a′(k).

An example of the relationship between a(k) and a′(k) is similar to theabove-described example. For example, the relationship between “the bitsand signal point arrangement for generating a(k)” and the relationshipbetween “the bits and signal point arrangement for generating a′(k)” maybe identical to or different from each other.

For another example, the modulation scheme for generating a(k) may bedifferent from the modulation scheme for generating a′(k).Alternatively, the signal point arrangement on the in-phase I quadratureQ plane for generating a(k) may be different from the signal pointarrangement on the in-phase I quadrature Q plane for generating a′(k).

A state where the signal point arrangement on the in-phase I quadratureQ plane is different means that, for example, the coordinates of sixteensignal points exist in the signal point arrangement on the in-phase Iquadrature Q plane for generating a(k), and at least one of the sixteensignal points existing in the signal point arrangement on the in-phase Iquadrature Q plane for generating a′(k) does not overlap any of thesixteen signal points in the signal point arrangement on the in-phase Iquadrature Q plane for generating a(k).

The relationship between b(k) and b′(k) is similar to theabove-described example. For example, the relationship between “the bitsand signal point arrangement for generating b(k)” and the relationshipbetween “the bits and signal point arrangement for generating b′(k)” maybe identical to or different from each other.

For another example, the modulation scheme for generating b(k) may bedifferent from the modulation scheme for generating b′(k).Alternatively, the signal point arrangement on the in-phase I quadratureQ plane for generating b(k) may be different from the signal pointarrangement on the in-phase I quadrature Q plane for generating b′(k).

A state where the signal point arrangement on the in-phase I quadratureQ plane is different means that, for example, the coordinates of sixteensignal points exist in the signal point arrangement on the in-phase Iquadrature Q plane for generating b(k), and at least one of the sixteensignal points existing in the signal point arrangement on the in-phase Iquadrature Q plane for generating b′(k) does not overlap any of thesixteen signal points in the signal point arrangement on the in-phase Iquadrature Q plane for generating b(k).

As described above, the mapped signal 5703A corresponds to the mappedsignal 205_1 in FIG. 2 , and the mapped signal 5703B corresponds to themapped signal 205_2 in FIG. 2 . Thus, the mapped signal 5703A and themapped signal 5703B are to be subjected to phase change, CDD processing,and weight combining processing performed as in FIGS. 3, 26, 38, 39, 40to 48, 49 to 54 , and so forth related to the signal processor 206 inFIG. 2 . However, in a case where ON/OFF of phase change is possible,phase change may be set to OFF, that is, phase change is not performed.In addition, in FIGS. 3, 26, 38, 39, 40 to 48 , and 49 to 54, aconfiguration not including a phase changer may be adopted.

Fifth Example

The fifth example is an example of the operation of the mapper 204 inthe configuration of the user #p signal processor 102_p illustrated inFIG. 62 , that is, the configuration including the two error-correctingencoders 202_1 and 202_2 and the one mapper 204.

In FIG. 62 , the elements similar to those in FIG. 2 are denoted by thesame numerals, and the description thereof is omitted.

The mapper 204 in FIG. 62 receives the coded data 203_1 and 203_2 andthe control signal 200. On the basis of information about a mappingmethod included in the control signal 200, the mapper 204 in FIG. 62performs mapping, and outputs the mapped signals 205_1 and 205_2.

FIG. 66 is a diagram illustrating the fifth example of the operation ofthe mapper 5702. The operation of the mapper 5702 illustrated in FIG. 66corresponds to an example of the operation of the mapper 204 illustratedin FIG. 62 . In FIG. 66 , the elements that operate similarly to thosein FIGS. 57 and 63 are denoted by the same numerals, and the descriptionthereof is omitted. In addition, the control signal 5700 corresponds tothe control signal 200 in FIG. 62 , the coded data 6301_1 corresponds tothe coded data 203_1 in FIG. 62 , the coded data 6301_2 corresponds tothe coded data 203_2 in FIG. 62 , the mapped signal 5703A corresponds tothe mapped signal 205_1 in FIG. 62 , and the mapped signal 5703Bcorresponds to the mapped signal 205_2 in FIG. 62 .

The mapper 5702 receives the coded data 6301_1 and 6301_2 and thecontrol signal 5700. In a case where a robust transmission method isdesignated by the control signal 5700, the mapper 5702 performs themapping described below, and outputs the mapped signals 5703A and 5703B.

For example, it is assumed that bit c0(k), bit c1(k), bit c2(k), and bitc3(k) are input as the coded data 6301_1 to the mapper 5702, and bitc4(k), bit c5(k), bit c6(k), and bit c7(k) are input as the coded data6301_2 to the mapper 5702. Here, k is an integer equal to or greaterthan 0.

It is assumed that the mapper 5702 performs modulation on bit c0(k), bitc1(k), bit c2(k), and bit c3(k) by using a modulation scheme havingsixteen signal points, such as 16QAM, to obtain a mapped signal a(k). Inaddition, it is assumed that the mapper 5702 performs modulation on bitc4(k), bit c5(k), bit c6(k), and bit c7(k) by using a modulation schemehaving sixteen signal points, such as 16QAM, to obtain a mapped signalb(k).

Also, it is assumed that the mapper 5702 performs modulation on bitc0(k), bit c1(k), bit c2(k), and bit c3(k) by using a modulation schemehaving sixteen signal points, such as 16QAM, to obtain a mapped signala′(k). In addition, it is assumed that the mapper 5702 performsmodulation on bit c4(k), bit c5(k), bit c6(k), and bit c7(k) by using amodulation scheme having sixteen signal points, such as 16QAM, to obtaina mapped signal b′(k).

The mapped signal 5703A with a symbol number i=2k is represented bys1(i=2k), and the mapped signal 5703B with a symbol number i=2k isrepresented by s2(i=2k). Also, the mapped signal 5703A with a symbolnumber i=2k+1 is represented by s1(i=2k+1), and the mapped signal 5703Bwith a symbol number i=2k+1 is represented by s2(i=2k+1).

Also, s1(i=2k), which is the mapped signal 5703A with a symbol numberi=2k, is represented by a(k), and s2(i=2k), which is the mapped signal5703B with a symbol number i=2k, is represented by b(k). Also,s1(i=2k+1), which is the mapped signal 5703A with a symbol numberi=2k+1, is represented by b′(k), and s2(i=2k+1), which is the mappedsignal 5703B with a symbol number i=2k+1, is represented by a′(k).

An example of the relationship between a(k) and a′(k) and an example ofthe relationship between b(k) and b′(k) are as described in the fourthexample.

As described above, the mapped signal 5703A corresponds to the mappedsignal 205_1 in FIG. 62 , and the mapped signal 5703B corresponds to themapped signal 205_2 in FIG. 62 . Thus, the mapped signal 5703A and themapped signal 5703B are to be subjected to phase change, CDD processing,and weight combining processing performed as in FIGS. 3, 26, 38, 39, 40to 48, 49 to 54 , and so forth related to the signal processor 206 inFIG. 62 . However, in a case where ON/OFF of phase change is possible,phase change may be set to OFF, that is, phase change is not performed.In addition, in FIGS. 3, 26, 38, 39, 40 to 48 , and 49 to 54, aconfiguration not including a phase changer may be adopted.

Sixth Example

The sixth example is, like the fifth example, an example of theoperation of the mapper 204 in the configuration of the user #p signalprocessor 102_p illustrated in FIG. 62 , that is, the configurationincluding the two error-correcting encoders 202_1 and 202_2 and the onemapper 204.

FIG. 67 is a diagram illustrating the sixth example of the operation ofthe mapper 5702. The operation of the mapper 5702 illustrated in FIG. 67corresponds to an example of the operation of the mapper 204 illustratedin FIG. 62 . In FIG. 67 , the elements that operate similarly to thosein FIGS. 57 and 63 are denoted by the same numerals, and the descriptionthereof is omitted. In addition, the control signal 5700 corresponds tothe control signal 200 in FIG. 62 , the coded data 6301_1 corresponds tothe coded data 203_1 in FIG. 62 , the coded data 6301_2 corresponds tothe coded data 203_2 in FIG. 62 , the mapped signal 5703A corresponds tothe mapped signal 205_1 in FIG. 62 , and the mapped signal 5701Bcorresponds to the mapped signal 205_2 in FIG. 62 .

The mapper 5702 receives the coded data 6301_1 and 6301_2 and thecontrol signal 5700. In a case where a robust transmission method isdesignated by the control signal 5700, the mapper 5702 performs themapping described below, and outputs the mapped signals 5703A and 5703B.

For example, bit c0(k), bit c1(k), bit c4(k), and bit c5(k) are input asthe coded data 6301_1 to the mapper 5702, and bit c2(k), bit c3(k), bitc6(k), and bit c7(k) are input as the coded data 6301_2 to the mapper5702. Here, k is an integer equal to or greater than 0.

It is assumed that the mapper 5702 performs modulation on bit c0(k), bitc1(k), bit c4(k), and bit c5(k) by using a modulation scheme havingsixteen signal points, such as 16QAM, to obtain a mapped signal a(k). Inaddition, it is assumed that the mapper 5702 performs modulation on bitc2(k), bit c3(k), bit c6(k), and bit c7(k) by using a modulation schemehaving sixteen signal points, such as 16QAM, to obtain a mapped signalb(k). Also, it is assumed that the mapper 5702 performs modulation onbit c0(k), bit c1(k), bit c4(k), and bit c5(k) by using a modulationscheme having sixteen signal points, such as 16QAM, to obtain a mappedsignal a′(k). In addition, it is assumed that the mapper 5702 performsmodulation on bit c2(k), bit c3(k), bit c6(k), and bit c7(k) by using amodulation scheme having sixteen signal points, such as 16QAM, to obtaina mapped signal b′(k).

In addition, the mapped signal 5703A with a symbol number i=2k isrepresented by s1(i=2k), and the mapped signal 5703B with a symbolnumber i=2k is represented by s2(i=2k). Also, the mapped signal 5703Awith a symbol number i=2k+1 is represented by s1(i=2k+1), and the mappedsignal 5703B with a symbol number i=2k+1 is represented by s2(i=2k+1).

In addition, s1(i=2k), which is the mapped signal 5703A with a symbolnumber i=2k, is represented by a(k), and s2(i=2k), which is the mappedsignal 5703B with a symbol number i=2k, is represented by b(k). Also,s1(i=2k+1), which is the mapped signal 5703A with a symbol numberi=2k+1, is represented by b′(k), and s2(i=2k+1), which is the mappedsignal 5703B with a symbol number i=2k+1, is represented by a′(k).

An example of the relationship between a(k) and a′(k) and an example ofthe relationship between b(k) and b′(k) are as described in the fourthexample.

As described above, the mapped signal 5703A corresponds to the mappedsignal 205_1 in FIG. 62 , and the mapped signal 5703B corresponds to themapped signal 205_2 in FIG. 62 . Thus, the mapped signal 5703A and themapped signal 5703B are to be subjected to phase change, CDD processing,and weight combining processing performed as in FIGS. 3, 26, 38, 39, 40to 48, 49 to 54 , and so forth related to the signal processor 206 inFIG. 62 . However, in a case where ON/OFF of phase change is possible,phase change may be set to OFF, that is, phase change is not performed.In addition, in FIGS. 3, 26, 38, 39, 40 to 48 , and 49 to 54, aconfiguration not including a phase changer may be adopted.

As described above in the present embodiment, when the transmissionapparatus transmits a modulated signal, the reception apparatus is ableto obtain high data reception quality. In particular, in an environmentin which direct waves are dominant, favorable data reception quality canbe obtained.

A case where a base station or AP is able to select a communicationmethod (transmission method) described in the present embodiment and acase where the terminal #p transmits a reception capability notificationsymbol described in the second embodiment, the third embodiment, and thefifth embodiment may be carried out in combination with each other.

For example, in a case where the terminal #p notifies the base stationor AP that the terminal #p supports phase change demodulation by usingthe information 2801 about “support/not support demodulation ofmodulated signal with phase change” in FIG. 30 or the terminal #pnotifies the base station or AP that the terminal #p supports thetransmission method (communication method) described in the presentembodiment by using the information 2901 about “support/not supportreception for multiple streams”, the base station or AP is able todecide to transmit multiple modulated signals for multiple streams byusing the transmission method (communication method) described in thepresent embodiment and is able to transmit the modulated signals.Accordingly, the terminal #p is able to obtain high data receptionquality. In addition, the base station or AP appropriately generates andtransmits modulated signals that can be received by the terminal #p inconsideration of the communication scheme supported by the terminal #pand a communication environment, and accordingly the data transmissionefficiency can be improved in the system constituted by the base stationor AP and the terminal #p.

In addition, the base station or AP may generate a modulated signal byusing the above-described method and transmit the modulated signal to aterminal A, and at the same time may generate a modulated signal byusing another method and transmit the modulated signal to anotherterminal.

Second Supplement

In this specification, a description is given of performing phase changein the phase changer 305A and/or the phase changer 305B in FIGS. 3, 26,38, 39, 40 to 48, 49 to 54 , and so forth related to the signalprocessor 206 in FIG. 2 . At this time, in a case where the period ofphase change in the phase changer 205A is represented by NA and in acase where NA is an integer equal to or greater than 3, that is, aninteger greater than 2, which is the number of streams to be transmittedor the number of modulated signals to be transmitted, there is a highpossibility that the reception apparatus as a communication partnerobtains favorable data reception quality. Likewise, in a case where theperiod of phase change in the phase changer 205B is represented by NBand in a case where NB is an integer equal to or greater than 3, thatis, an integer greater than 2, which is the number of streams to betransmitted or the number of modulated signals to be transmitted, thereis a high possibility that the reception apparatus as a communicationpartner obtain favorable data reception quality.

In this specification, in a case where weight combining (precoding)processing is performed by using only the (precoding) matrix Fp ofExpression (33) or Expression (34) in FIGS. 3, 26, 38, 39, 40 to 48 ,and so forth related to the signal processor 206 in FIGS. 2, 56 , and soforth, the signal processor 206 in FIGS. 2, 56 , and so forth need notnecessarily include the weight combiner 303.

In this specification, a description has been given mainly of performingphase change in the phase changer 305A and/or the phase changer 305Band/or the phase changer 3801A and/or the phase changer 3801B in FIGS.3, 26, 38, 39, 40 to 48 , and so forth related to the signal processor206 in FIGS. 2, 56 , and so forth. However, switching between performand not perform phase change may be controlled by the control signal 300input to the phase changer 305A, the phase changer 305B, the phasechanger 3801A, or the phase changer 3801B. Thus, for example, thecontrol signal 300 may include control information about “perform or notperform phase change in the phase changer 305A”, control informationabout “perform or not perform phase change in the phase changer 305B”,control information about “perform or not perform phase change in thephase changer 3801A”, or control information about “perform or notperform phase change in the phase changer 3801B”. In addition, “performor not perform phase change in the phase changer 305A, the phase changer305B, the phase changer 3801A, or the phase changer 3801B” may becontrolled by such control information.

For example, in a case where the phase changer 3801A receives thecontrol signal 300 and receives an instruction not to perform phasechange through the control signal 300, the phase changer 3801A outputsthe input signal 301A as 3802A. Also, in a case where the phase changer3801B receives the control signal 300 and receives an instruction not toperform phase change through the control signal 300, the phase changer3801B outputs the input signal 301B as 3802B. In a case where the phasechanger 305A receives the control signal 300 and receives an instructionnot to perform phase change through the control signal 300, the phasechanger 305A outputs the input signal 304A as 306A. In a case where thephase changer 305B receives the control signal 300 and receives aninstruction not to perform phase change through the control signal 300,the phase changer 305B outputs the input signal 304B as 306B.

In this specification, a description has been given mainly of performingphase change in the phase changer 309A and the phase changer 309B inFIGS. 3, 26, 38, 39, 49, 50, 51, 52, 53 , and so forth. Also, adescription has been given mainly of performing CDD (CSD) processing inthe CDD (CSD) section 4909A and the CDD (CSD) section 4909B. However,switching between perform and not perform phase change may be controlledby the control signal 300 input to the phase changer 309A or the phasechanger 309B.

Thus, for example, the control signal 300 may include controlinformation about “perform or not perform phase change in the phasechanger 309A” or control information about “perform or not perform phasechange in the phase changer 309B”, and “perform or not perform phasechange in the phase changer 309A or the phase changer 309B” may becontrolled by such control information.

In addition, switching between perform and not perform CDD (CSD)processing may be controlled by the control signal 300 input to the CDD(CSD) section 4909A or the CDD (CSD) section 4909B. Thus, for example,the control signal 300 may include control information about “perform ornot perform CDD (CSD) processing in the CDD (CSD) section 4909A” orcontrol information about “perform or not perform CDD (CSD) processingin the CDD (CSD) section 4909B”, and “perform or not perform CDD (CSD)processing in the CDD (CSD) section 4909A or 4909B” may be controlled bysuch control information.

For example, in a case where the phase changer 309A receives the controlsignal 300 and receives an instruction not to perform phase changethrough the control signal 300, the phase changer 309A outputs the inputsignal 308A as 310A. In a case where the phase changer 309B receives thecontrol signal 300 and receives an instruction not to perform phasechange through the control signal 300, the phase changer 309B outputsthe input signal 308B as 310B. In a case where the CDD (CSD) section4909A receives the control signal 300 as input and receives aninstruction not to perform CDD (CSD) processing through the controlsignal 300, the CDD (CSD) section 4909A outputs the input signal 308A as4910A. In a case where the CDD (CSD) section 4909B receives the controlsignal 300 and receives an instruction not to perform CDD (CSD)processing through the control signal 300, the CDD (CSD) section 4909Boutputs the input signal 308B as 4910B.

Obviously, the embodiments described in this specification and otherthings described in supplements may be carried out in combination withone another.

In the description of this specification, the terms “base station (orAP)” and “terminal” are used for describing the individual embodiments,and these are not limited to such terms. Thus, in the individualembodiments, the operation described as the operation of “base station(or AP)” may be the operation of “terminal”, “communication apparatus”,“broadcast station”, “mobile phone”, “personal computer”, “televisionreceiver”, or the like. Also, in the individual embodiments, theoperation described as the operation of “terminal” may be the operationof “base station (or AP)”, “communication apparatus”, “broadcaststation”, “mobile phone”, “personal computer”, “television receiver”, orthe like.

Thirteenth Embodiment

The phase change performed by the phase changers 305A, 305B, 3801A, and3801B have been described above with reference to FIGS. 3, 26, 38, 39,40 to 48 , and so forth. In the present embodiment, a description willbe given of an example of a transmission state and an example of areception state at that time. As an example, the operation in FIG. 3will be described.

First, a description will be given of, for comparison, a case wherephase change is not performed by the phase changer 305B in FIG. 3 .

FIG. 68A is a diagram illustrating a first example of the state ofsignal points of signals transmitted by the transmission apparatusincluding the configuration in FIG. 3 . FIG. 68B is a diagramillustrating a first example of the state of signal points of signalsreceived by the reception apparatus as a communication partner of thetransmission apparatus including the configuration in FIG. 3 . In FIGS.68A and 68B, the state of signal points on the in-phase I quadrature Qplane is sequentially illustrated in the horizontal-axis direction foreach symbol number.

The example illustrated in FIGS. 68A and 68B is an example of a casewhere, in the transmission apparatus, the phase changer 305B in FIG. 3does not operate, and the weight combiner 303 performs weight combiningof any of Expressions (33), (34), (35), and (36). In addition, themodulation scheme applied to sp1(i) of the mapped signal 301A is QPSK,and the modulation scheme applied to sp2(i) of the mapped signal 301B isQPSK.

In FIG. 68A, 6800_1 denotes the state of signal points of zp1(i) of thesignal 304A with a symbol number #0, and • represents a signal point.There are four signal points. In FIG. 68A, 6800_2 denotes the state ofsignal points of zp2(i) of the signal 306B with the symbol number #0,and • represents a signal point. There are four signal points. In FIG.68A, 6801_1 denotes the state of signal points of zp1(i) of the signal304A with a symbol number #1, and • represents a signal point. There arefour signal points. In FIG. 68A, 6801_2 denotes the state of signalpoints of zp2(i) of the signal 306B with the symbol number #1, and •represents a signal point. There are four signal points. In FIG. 68A,6802_1 denotes the state of signal points of zp1(i) of the signal 304Awith a symbol number #2, and • represents a signal point. There are foursignal points. In FIG. 68A, 6802_2 denotes the state of signal points ofzp2(i) of the signal 306B with the symbol number #2, and • represents asignal point. There are four signal points.

FIG. 68B illustrates the state of signal points at the time of receptioncorresponding to the state of signal points of the transmitted signalsillustrated in FIG. 68A. To simplify the description, the channel matrixof Expression (41) is expressed by the following Expression (63) as anexample of an LOS environment.

$\begin{matrix}{\begin{pmatrix}{h11(i)} & {h12(i)} \\{h21(i)} & {h22(i)}\end{pmatrix} = \begin{pmatrix}1 & 1 \\1 & 1\end{pmatrix}} & {{Expression}(63)}\end{matrix}$

In FIG. 68B, 6810_1 denotes the state of signal points at the time ofreception of Rx1(i), which is the reception signal 1902X in FIG. 19 withthe symbol number #0, and • represents a signal point. There are ninesignal points. In FIG. 68B, 6810_2 denotes the state of signal points atthe time of reception of Rx2(i), which is the reception signal 1902Y inFIG. 19 with the symbol number #0, and • represents a signal point.There are nine signal points. In FIG. 68B, 6811_1 denotes the state ofsignal points at the time of reception of Rx1(i), which is the receptionsignal 1902X in FIG. 19 with the symbol number #1, and • represents asignal point. There are nine signal points. In FIG. 68B, 6811_2 denotesthe state of signal points at the time of reception of Rx2(i), which isthe reception signal 1902Y in FIG. 19 with the symbol number #1, and •represents a signal point. There are nine signal points. In FIG. 68B,6812_1 denotes the state of signal points at the time of reception ofRx1(i), which is the reception signal 1902X in FIG. 19 with the symbolnumber #2, and • represents a signal point. There are nine signalpoints. In FIG. 68B, 6812_2 denotes the state of signal points at thetime of reception of Rx2(i), which is the reception signal 1902Y in FIG.19 with the symbol number #2, and • represents a signal point. There arenine signal points.

In a case where modulated signals are transmitted in the mannerillustrated in FIG. 68A, the signal points in the reception apparatusare those illustrated in FIG. 68B. In this case, the number of signalpoints at the time of reception is nine, and this state has acharacteristic of not changing even if the symbol number changes.Ideally, there are sixteen signal points. In this state, it is difficultto obtain high data reception quality at the reception apparatus.

Next, a description will be given of a case where phase change isperformed by the phase changer 305B in FIG. 3 .

FIG. 69A is a diagram illustrating a second example of the state ofsignal points of signals transmitted by the transmission apparatusincluding the configuration in FIG. 3 . FIG. 69B is a diagramillustrating a second example of the state of signal points of signalsreceived by the reception apparatus as a communication partner of thetransmission apparatus including the configuration in FIG. 3 . In FIGS.69A and 69B, the state of signal points on the in-phase I quadrature Qplane is sequentially illustrated in the horizontal-axis direction foreach symbol number.

The example illustrated in FIGS. 69A and 69B is an example of a casewhere, in the transmission apparatus, the phase changer 305B operates,and the weight combiner 303 performs weight combining of any ofExpressions (33), (34), (35), and (36). In addition, the modulationscheme applied to sp1(i) of the mapped signal 301A is QPSK, and themodulation scheme applied to sp2(i) of the mapped signal 301B is QPSK.

In FIG. 69A, 6900_1 denotes the state of signal points of zp1(i) of thesignal 304A with the symbol number #0, and • represents a signal point.There are four signal points. In FIG. 69A, 6900_2 denotes the state ofsignal points of zp2(i) of the signal 306B with the symbol number #0,and • represents a signal point. There are four signal points. In FIG.69A, 6901_1 denotes the state of signal points of zp1(i) of the signal304A with the symbol number #1, and • represents a signal point. Thereare four signal points. In FIG. 69A, 6901_2 denotes the state of signalpoints of zp2(i) of the signal 306B with the symbol number #1, and •represents a signal point. There are four signal points. Since the phasechanger 305B operates and performs phase change, the phase of the signalpoints denoted by 6901_2 is changed from the signal points denoted by6900_2. In FIG. 69A, 6902_1 denotes the state of signal points of zp1(i)of the signal 304A with the symbol number #2, and • represents a signalpoint. There are four signal points. In FIG. 69A, 6902_2 denotes thestate of signal points of zp2(i) of the signal 306B with the symbolnumber #2, and • represents a signal point. There are four signalpoints. Since the phase changer 305B operates and performs phase change,the phase of the signal points denoted by 6902_2 is changed from thesignal points denoted by 6901_2.

FIG. 69B illustrates the state of signal points at the time of receptioncorresponding to the state of signal points of the transmitted signalsillustrated in FIG. 69A. To simplify the description, the channel matrixis expressed by Expression (63) as an example of an LOS environment.

In FIG. 69B, 6910_1 denotes the state of signal points at the time ofreception of Rx1(i), which is the reception signal 1902X in FIG. 19 withthe symbol number #0, and • represents a signal point. There are ninesignal points. In FIG. 69B, 6910_2 denotes the state of signal points atthe time of reception of Rx2(i), which is the reception signal 1902Y inFIG. 19 with the symbol number #0, and • represents a signal point.There are nine signal points. In FIG. 69B, 6911_1 denotes the state ofsignal points at the time of reception of Rx1(i), which is the receptionsignal 1902X in FIG. 19 with the symbol number #1, and • represents asignal point. There are sixteen signal points. The positions and thenumber of signal points are changed from 6910_1. This is because, asillustrated in FIG. 69A, the phase of the signal points denoted by6901_2 is changed from the signal points denoted by 6900_2. In FIG. 69B,6911_2 denotes the state of signal points at the time of reception ofRx2(i), which is the reception signal 1902Y in FIG. 19 with the symbolnumber #1, and • represents a signal point. There are sixteen signalpoints. The positions and the number of signal points are changed from6910_2. This is because, as illustrated in FIG. 69A, the phase of thesignal points denoted by 6901_2 is changed from the signal pointsdenoted by 6900_2. In FIG. 69B, 6912_1 denotes the state of signalpoints at the time of reception of Rx1(i), which is the reception signal1902X in FIG. 19 with the symbol number #2, and • represents a signalpoint. There are sixteen signal points. The positions of signal pointsare changed from 6911_1. This is because, as illustrated in FIG. 69A,the phase of the signal points denoted by 6902_2 is changed from thesignal points denoted by 6901_2. In FIG. 69B, 6912_2 denotes the stateof signal points at the time of reception of Rx2(i), which is thereception signal 1902Y in FIG. 19 with the symbol number #2, and •represents a signal point. There are sixteen signal points. Thepositions of signal points are changed from 6911_2. This is because, asillustrated in FIG. 69A, the phase of the signal points denoted by6902_2 is changed from the signal points denoted by 6901_2.

In a case where modulated signals are transmitted in the mannerillustrated in FIG. 69A, the signal points in the reception apparatusare those illustrated in FIG. 69B, and the number of signal points maybe sixteen. If the symbol number changes, the positions of signal pointson the in-phase I quadrature Q plane change.

In this way, in a state where the radio wave condition is steady as inan LOS environment, phase change performed in the transmission apparatuscauses a change in the state of signal points at the time of receptionin the reception apparatus. Thus, there is an increased possibility thatthe data reception quality at the reception apparatus is improved.

The description given above is merely an example. To induce theabove-described situation “in a steady state such as an LOS environment,the state at the time of reception in the reception apparatus changes”,a method of performing phase change by the phase changers 305A, 305B,3801A, and 3801B may be used as in FIGS. 3, 26, 38, 39, 40 to 48 , andso forth, for example. Also with this configuration, a possibility ofimproving the data reception quality is increased, as described above.

Description of Operation of Reception Apparatus

As described above, the reception apparatus illustrated in FIG. 19receives, as a result of phase change, a reception signal in which thesignal point arrangement at the time of reception changes. Hereinafter,a supplemental description will be given of the operation of thereception apparatus in FIG. 19 . A description will be given of a casewhere the transmission apparatus has the configuration illustrated inFIG. 3, 26 , or the like, that is, the transmission apparatus has aconfiguration in which a phase changer is arranged downstream of aweight combiner and generates and transmits modulated signals.

The transmission apparatus transmits modulated signals with the frameconfigurations in (FIGS. 8 and 9 ) or (FIGS. 10 and 11 ), for example.

In the reception apparatus of the terminal #p in FIG. 19 , the controlinformation decoder 1909 obtains, from the control information symbol in(FIGS. 8 and 9 ) or (FIGS. 10 and 11 ), information about thetransmission method, modulation scheme, error-correcting coding method,and so forth used to generate data symbols. In a case where thetransmission apparatus performs phase change, the control informationdecoder 1909 obtains information about “what phase change has beenperformed on data symbols” included in the control information symbol,and outputs a control signal 1901 including information about a phasechange method so that the data symbols can be demodulated inconsideration of phase change. It is assumed that the control signal1901 includes information about the transmission method, modulationscheme, error-correcting coding method, and so forth.

As described in FIG. 20 , the reception signals r1(i) and r2(i) areexpressed by Expression (41). On the basis of Expression (3), Expression(41), and Expression (42), the reception signals r1(i) and r2(i) areexpressed by the following Expression (64).

$\begin{matrix}\begin{matrix}{\begin{pmatrix}{r1(i)} \\{r2(i)}\end{pmatrix} = {{\begin{pmatrix}{h11(i)} & {h12(i)} \\{h21(i)} & {h22(i)}\end{pmatrix}\begin{pmatrix}{{Yp}(i)} & 0 \\0 & {{yp}(i)}\end{pmatrix}{{Fp}\begin{pmatrix}{{sp}1(i)} \\{{sp}2(i)}\end{pmatrix}}} + \begin{pmatrix}{n1(i)} \\{n2(i)}\end{pmatrix}}} \\{= {{\begin{pmatrix}{h11(i)} & {h12(i)} \\{h21(i)} & {h22(i)}\end{pmatrix}\begin{pmatrix}{{Yp}(i)} & 0 \\0 & {{yp}(i)}\end{pmatrix}\begin{pmatrix}a & b \\c & d\end{pmatrix}\begin{pmatrix}{{sp}1(i)} \\{{sp}2(i)}\end{pmatrix}} + \begin{pmatrix}{n1(i)} \\{n2(i)}\end{pmatrix}}}\end{matrix} & {{Expression}(64)}\end{matrix}$

In a case where the phase changer 305A does not perform phase change (orin a case where the phase changer 305A does not exist), Yp(i)=1. In acase where the phase changer 305B does not perform phase change (or in acase where the phase changer 305B does not exist), yp(i)=1.

The modulated signal u1 channel estimator 1905_1 estimates h11(i) inExpression (64) by using the preamble and pilot symbols in (FIGS. 8 and9 ) or (FIGS. 10 and 11 ) and outputs it (see 1906_1 in FIG. 19 ). Themodulated signal u2 channel estimator 1905_2 estimates h12(i) inExpression (64) by using the preamble and pilot symbols in (FIGS. 8 and9 ) or (FIGS. 10 and 11 ) and outputs it (see 1906_2 in FIG. 19 ). Themodulated signal u1 channel estimator 1907_1 estimates h21(i) inExpression (64) by using the preamble and pilot symbols in (FIGS. 8 and9 ) or (FIGS. 10 and 11 ) and outputs it (see 1908_1 in FIG. 19 ). Themodulated signal u2 channel estimator 1907_2 estimates h22(i) inExpression (64) by using the preamble and pilot symbols in (FIGS. 8 and9 ) or (FIGS. 10 and 11 ) and outputs it (see 1908_2 in FIG. 19 ).

The signal processor 1911 learns the relationship in Expression (64)from input signals, and thus demodulates sp1(i) and sp2(i) on the basisof the relationship in Expression (64) and then performserror-correcting decoding to obtain and output the reception data 1912.

A description will be given of a case where the transmission apparatushas the configuration in any of FIGS. 40 to 48 , that is, aconfiguration in which phase changers are arranged both upstream anddownstream of the weight combiner, and generates and transmits modulatedsignals.

The transmission apparatus transmits modulated signals with the frameconfigurations in (FIGS. 8 and 9 ) or (FIGS. 10 and 11 ), for example.

In the reception apparatus of the terminal #p in FIG. 19 , the controlinformation decoder 1909 obtains, from the control information symbol in(FIGS. 8 and 9 ) or (FIGS. 10 and 11 ), information about thetransmission method, modulation scheme, error-correcting coding method,and so forth used to generate data symbols. In a case where thetransmission apparatus performs phase change, the control informationdecoder 1909 obtains information about “what phase change has beenperformed on data symbols” included in the control information symbol,and outputs the control signal 1901 including information about a phasechange method so that the data symbols can be demodulated inconsideration of phase change. It is assumed that the control signal1901 includes information about the transmission method, modulationscheme, error-correcting coding method, and so forth.

As described in FIG. 20 , the reception signals r1(i) and r2(i) areexpressed by Expression (41). At this time, on the basis of Expression(3), Expression (41), Expression (42), and Expression (51), thereception signals r1(i) and r2(i) are expressed by the followingExpression (65).

$\begin{matrix}\begin{matrix}{\begin{pmatrix}{r1(i)} \\{r2(i)}\end{pmatrix} = {\begin{pmatrix}{h11(i)} & {h12(i)} \\{h21(i)} & {h22(i)}\end{pmatrix}\begin{pmatrix}{{Yp}(i)} & 0 \\0 & {{yp}(i)}\end{pmatrix}{{Fp}\begin{pmatrix}{{Vp}(i)} & 0 \\0 & {{vp}(i)}\end{pmatrix}}}} \\{\begin{pmatrix}{{sp}1(i)} \\{{sp}2(i)}\end{pmatrix} + \begin{pmatrix}{n1(i)} \\{n2(i)}\end{pmatrix}} \\{= {\begin{pmatrix}{h11(i)} & {h12(i)} \\{h21(i)} & {h22(i)}\end{pmatrix}\begin{pmatrix}{{Yp}(i)} & 0 \\0 & {{yp}(i)}\end{pmatrix}\begin{pmatrix}a & b \\c & d\end{pmatrix}}} \\{{\begin{pmatrix}{{Vp}(i)} & 0 \\0 & {{vp}(i)}\end{pmatrix}\begin{pmatrix}{{sp}1(i)} \\{{sp}2(i)}\end{pmatrix}} + \begin{pmatrix}{n1(i)} \\{n2(i)}\end{pmatrix}}\end{matrix} & {{Expression}(65)}\end{matrix}$

In a case where the phase changer 305A does not perform phase change (orin a case where the phase changer 305A does not exist), Yp(i)=1. In acase where the phase changer 305B does not perform phase change (or in acase where the phase changer 305B does not exist), yp(i)=1. In a casewhere the phase changer 3801A does not perform phase change (or in acase where the phase changer 3801A does not exist), Vp(i)=1. In a casewhere the phase changer 3801B does not perform phase change (or in acase where the phase changer 3801B does not exist), vp(i)=1.

The modulated signal u1 channel estimator 1905_1 estimates h11(i) inExpression (65) by using the preamble and pilot symbols in (FIGS. 8 and9 ) or (FIGS. 10 and 11 ) and outputs it (see 1906_1 in FIG. 19 ). Themodulated signal u2 channel estimator 1905_2 estimates h12(i) inExpression (65) by using the preamble and pilot symbols in (FIGS. 8 and9 ) or (FIGS. 10 and 11 ) and outputs it (see 1906_2 in FIG. 19 ). Themodulated signal u1 channel estimator 1907_1 estimates h21(i) inExpression (65) by using the preamble and pilot symbols in (FIGS. 8 and9 ) or (FIGS. 10 and 11 ) and outputs it (see 1908_1 in FIG. 19 ). Themodulated signal u2 channel estimator 1907_2 estimates h22(i) inExpression (65) by using the preamble and pilot symbols in (FIGS. 8 and9 ) or (FIGS. 10 and 11 ) and outputs it (see 1908_2 in FIG. 19 ).

The signal processor 1911 learns the relationship in Expression (65)from input signals, and thus demodulates sp1(i) and sp2(i) on the basisof the relationship in Expression (65) and then performserror-correcting decoding to obtain and output the reception data 1912.

Fourteenth Embodiment

In the present embodiment, a description will be given of aconfiguration of the transmission apparatus, such as a base station, anaccess point, or a broadcast station, different from the configurationin FIG. 1 .

FIG. 70 is a diagram illustrating an example configuration of thetransmission apparatus of a base station (AP), different from theconfiguration in FIG. 1 . In FIG. 70 , the elements similar to those inFIG. 1 are denoted by the same numerals, and the description thereof isomitted.

FIG. 70 is different from FIG. 1 in that multiplexing signal processorsfor individual users (multiplexing signal processors 7000_1 to 7000_M)are provided in FIG. 70 instead of the multiplexing signal processor 104in FIG. 1 , and that adders (adders 7002_1 to 7002_N) are provideddownstream of the multiplexing signal processors.

The multiplexing signal processor 7000_1 receives the control signal100, the user #1 first baseband signal 103_1_1, the user #1 secondbaseband signal 103_1_2, and the (common) reference signal 199. On thebasis of the control signal 100, the multiplexing signal processor7000_1 performs multiplexing signal processing on the user #1 firstbaseband signal 103_1_1 and the user #1 second baseband signal 103_1_2,and generates and outputs a user #1 multiplexed signal $1 basebandsignal 7001_1_1 to a user #1 multiplexed signal $N baseband signal7001_1_N. Here, N is an integer equal to or greater than 1. In a casewhere q is an integer from 1 to N, a user #1 multiplexed signal $qbaseband signal 7001_1_q exists. In addition, the user #1 multiplexedsignal $1 baseband signal 7001_1_1 to the user #1 multiplexed signal $Nbaseband signal 7001_1_N may include a reference signal.

Likewise, the multiplexing signal processor 7000_2 receives the controlsignal 100, the user #2 first baseband signal 103_2_1, the user #2second baseband signal 103_2_2, and the (common) reference signal 199.On the basis of the control signal 100, the multiplexing signalprocessor 7000_2 performs multiplexing signal processing on the user #2first baseband signal 103_2_1 and the user #2 second baseband signal103_2_2, and generates and outputs a user #2 multiplexed signal $1baseband signal 7001_2_1 to a user #2 multiplexed signal $N basebandsignal 7001_2_N. Here, N is an integer equal to or greater than 1. In acase where q is an integer from 1 to N, a user #2 multiplexed signal $qbaseband signal 7001_2_q exists. In addition, the user #2 multiplexedsignal $1 baseband signal 7001_2_1 to the user #2 multiplexed signal $Nbaseband signal 7001_2_N may include a reference signal.

Likewise, the multiplexing signal processor 7000_M receives the controlsignal 100, the user #M first baseband signal 103_M_1, the user #Msecond baseband signal 103_M_2, and the (common) reference signal 199.On the basis of the control signal 100, the multiplexing signalprocessor 7000_M performs multiplexing signal processing on the user #Mfirst baseband signal 103_M_1 and the user #M second baseband signal103_M_2, and generates and outputs a user #M multiplexed signal $1baseband signal 7001_M_1 to a user #M multiplexed signal $N basebandsignal 7001_M_N. Here, N is an integer equal to or greater than 1. In acase where q is an integer from 1 to N, a user #M multiplexed signal $qbaseband signal 7001_M_q exists. In addition, the user #M multiplexedsignal $1 baseband signal 7001_M_1 to the user #M multiplexed signal $Nbaseband signal 7001_M_N may include a reference signal.

Thus, a multiplexing signal processor 7000_p (p is an integer from 1 toM) receives the control signal 100, a user #p first baseband signal103_p_1, and a user #p second baseband signal 103_p_2. On the basis ofthe control signal 100, the multiplexing signal processor 7000_pperforms multiplexing signal processing on the user #p first basebandsignal 103_p_1 and the user #p second baseband signal 103_p_2, andgenerates and outputs a user #p multiplexed signal $1 baseband signal7001_p_1 to a user #p multiplexed signal $N baseband signal 7001_p_N.Here, N is an integer equal to or greater than 1. In a case where q isan integer from 1 to N, a user #p multiplexed signal $q baseband signal7001_p_q exists. In addition, the user #p multiplexed signal $1 basebandsignal 7001_p_1 to the user #p multiplexed signal $N baseband signal7001_p_N may include a reference signal.

The adder 7002_1 receives the user #1 multiplexed signal $1 basebandsignal 7001_1_1 to the user #M multiplexed signal $1 baseband signal7001_M_1. That is, in a case where p is an integer from 1 to M, theadder 7002_1 receives the user #p multiplexed signal $1 baseband signal7001_p_1. The adder 7002_1 adds the user #1 multiplexed signal $1baseband signal 7001_1_1 to the user #M multiplexed signal $1 basebandsignal 7001_M_1 and outputs a first added signal 7003_1.

Likewise, the adder 7002_2 receives the user #1 multiplexed signal $2baseband signal 7001_1_2 to the user #M multiplexed signal $2 basebandsignal 7001_M_2. That is, in a case where p is an integer from 1 to M,the adder 7002_2 receives the user #p multiplexed signal $2 basebandsignal 7001_p_2. The adder 7002_2 adds the user #1 multiplexed signal $2baseband signal 7001_1_2 to the user #M multiplexed signal $2 basebandsignal 7001_M_2 and outputs a second added signal 7003_2.

The adder 7002_N receives the user #1 multiplexed signal $N basebandsignal 7001_1_N to the user #M multiplexed signal $N baseband signal7001_M_N. That is, in a case where p is an integer from 1 to M, theadder 7002_N receives the user #p multiplexed signal $N baseband signal7001_p_N. The adder 7002_N adds the user #1 multiplexed signal $Nbaseband signal 7001_1_N to the user #M multiplexed signal $N basebandsignal 7001_M_N and outputs an N-th added signal 7003_N.

Thus, an adder 7002_q receives the user #1 multiplexed signal $qbaseband signal 7001_1_q to the user #M multiplexed signal $q basebandsignal 7001_M_q. That is, in a case where p is an integer from 1 to M,the adder 7002_q receives the user #p multiplexed signal $q basebandsignal 7001_p_q. The adder 7002_q adds the user #1 multiplexed signal $qbaseband signal 7001_1_q to the user #M multiplexed signal $q basebandsignal 7001_M_q and outputs a q-th added signal 7003_q. At this time, qis an integer from 1 to N.

The radio section $1 (106_1) receives the control signal 100 and thefirst added signal 7003_1, performs processing such as frequencyconversion and amplification on the first added signal 7003_1 on thebasis of the control signal 100, and outputs the transmission signal107_1.

Likewise, the radio section $2 (106_2) receives the control signal 100and the second added signal 7003_2, performs processing such asfrequency conversion and amplification on the second added signal 7003_2on the basis of the control signal 100, and outputs the transmissionsignal 107_2.

Likewise, the radio section $N (106_N) receives the control signal 100and the N-th added signal 7003_N, performs processing such as frequencyconversion and amplification on the N-th added signal 7003_N on thebasis of the control signal 100, and outputs the transmission signal107_N.

Thus, a radio section $q (106_q) receives the control signal 100 and theq-th added signal 7003_q, performs processing such as frequencyconversion and amplification on the q-th added signal 7003_q on thebasis of the control signal 100, and outputs a transmission signal107_q. At this time, q is an integer from 1 to N.

Next, a description will be given of an example of the operation of themultiplexing signal processor 7000_p.

For example, on the basis of Expression (3), Expression (42), or thelike, the user #p first baseband signal 103_p_1 and the user #p secondbaseband signal 103_p_2 output from the user #p signal processor 102_p(p is an integer from 1 to M) in FIG. 70 are represented by zp1(i) andzp2(i), respectively. Note that zp1(i) and zp2(i) may be generated byprocessing other than Expression (3) and Expression (42), and zp1(i)=0and zp2(i)=0 may hold. When zp1(i)=0, zp1(i) does not exist. Whenzp2(i)=0, zp2(i) does not exist.

When the user #p multiplexed signal $q baseband signal 7001_p_q outputfrom the multiplexing signal processor 7000_p is represented by gpq(i),gpq(i) is expressed by the following Expression (66).

gpq(i)=a_p_q_1(i)×zp1(i)+a_p_q_2(i)×zp2(i)  Expression (66)

At this time, a_p_q_1(i) and a_p_q_2(i) are weighting coefficients formultiplexing and may be defined as complex numbers. Thus, a_p_q_1(i) anda_p_q_2(i) may be real numbers. Here, a_p_q_1(i) and a_p_q_2(i) are eachexpressed by a function of a symbol number i, but the value need notnecessarily change for each symbol. In addition, a_p_q_1(i) anda_p_q_2(i) are decided on the basis of feedback information of eachterminal.

In FIG. 70 , the number of user #p baseband signals output from the user#p signal processor 102_p is not limited to two. For example, it isassumed that the number of user #p baseband signals output from the user#p signal processor 102_p is equal to or smaller than S. Here, S is aninteger equal to or greater than 1. The user #p k-th baseband signal (kis an integer from 1 to S) is represented by zpk(i).

At this time, when the user #p multiplexed signal $q baseband signal7001_p_q output from the multiplexing signal processor 7000_p isrepresented by gpq(i), gpq(i) is expressed by the following Expression(67).

$\begin{matrix}{{{gpq}(i)} = {\sum\limits_{k = 1}^{S}{{a\_ p}{\_ q}{\_ k}(i) \times {{zpk}(i)}}}} & {{Expression}(67)}\end{matrix}$

At this time, a_p_q_k(i) is a weighting coefficient for multiplexing andmay be defined as a complex number. Thus, a_p_q_k(i) may be a realnumber. Here, a_p_q_k(i) is each expressed by a function of a symbolnumber i, but the value need not necessarily change for each symbol. Inaddition, a_p_q_k(i) is decided on the basis of feedback information ofeach terminal.

Next, a description will be given of an example of the operation of theadder 7002_q.

The q-th added signal 7003_q output from the adder 7002_q in FIG. 70 isrepresented by eq(i). Then, eq(i) is expressed by the followingExpression (68).

$\begin{matrix}{{{eq}(i)} = {\sum\limits_{k = 1}^{M}{{gkq}(i)}}} & {{Expression}(68)}\end{matrix}$

As described above, also with the configuration in FIG. 70 of thetransmission apparatus of the base station or AP, the individualembodiments described in this specification can be carried outsimilarly, and the effects described in the individual embodiments canbe obtained similarly

Third Supplement

In this specification, FIG. 35 illustrates an example of theconfiguration of the reception apparatus of the terminal #p, which is acommunication partner of the base station or AP, in a case where thetransmission apparatus of the base station or AP transmits a modulatedsignal of a single stream. The configuration of the terminal #p thatreceives the modulated signal of the single stream is not limited tothat in FIG. 35 . For example, the reception apparatus of the terminal#p may include multiple reception antennas. For example, in FIG. 19 , ina case where the modulated signal u2 channel estimators 1905_2 and1907_2 do not operate, a channel estimator for one modulated signaloperates. With this configuration, a modulated signal of a single streamcan be received.

Thus, in the description of this specification, the embodiment describedusing FIG. 35 can be carried out similarly by using the above-describedconfiguration of the reception apparatus instead of the configuration inFIG. 35 , and similar effects can be obtained.

Fifteenth Embodiment

In the present embodiment, a description will be given of another methodfor performing the operation of the terminal #p described in the thirdembodiment, the fifth embodiment, and so forth.

An example of the configuration of the terminal #p has already beendescribed by using FIG. 34 and so forth, and thus the descriptionthereof is omitted. Also, an example of the configuration of thereception apparatus 3404 of the terminal #p in FIG. 34 has beendescribed by using FIG. 35 and so forth, and thus the descriptionthereof is omitted.

An example of the frame configuration that is used when the base stationor AP as a communication partner of the terminal #p transmits amodulated signal of a single stream using the multi-carrier scheme suchas the OFDM scheme has been described by using FIG. 36 and so forth, andthus the description thereof is omitted.

For example, the transmission apparatus of the base station (AP) in FIG.1 may transmit a modulated signal of a single stream having the frameconfiguration in FIG. 36 .

An example of the frame configuration that is used when the base stationor AP as a communication partner of the terminal #p transmits amodulated signal of a single stream using the single-carrier scheme hasbeen described by using FIG. 37 and so forth, and thus the descriptionthereof is omitted.

For example, the transmission apparatus of the base station (AP) in FIG.1 may transmit a modulated signal of a single stream having the frameconfiguration in FIG. 37 .

In addition, for example, the transmission apparatus of the base station(AP) in FIG. 1 may transmit modulated signals of multiple streams havingthe frame configurations in FIGS. 8 and 9 .

Furthermore, for example, the transmission apparatus of the base station(AP) in FIG. 1 may transmit modulated signals of multiple streams havingthe frame configurations in FIGS. 10 and 11 .

FIG. 71 is a diagram illustrating an example of the data included in thereception capability notification symbol 2702 transmitted by theterminal #p in FIG. 27 , different from the examples in FIGS. 28, 29,and 30 . The elements similar to those in FIGS. 28, 29 , and 30 aredenoted by the same numerals. The elements that function similarly tothose in FIGS. 28, 29, and 30 will not be described.

The example of data illustrated in FIG. 71 has a configuration in whichdata 5301 about “supported precoding methods” is added to the example ofdata in FIG. 30 . Hereinafter, a description will be given of the data5301 about “supported precoding methods”.

It is assumed that, when the base station or AP transmits multiplemodulated signals for multiple streams, the base station or AP is ableto select one precoding method from among multiple precoding methods,perform weight combining (for example, by the weight combiner 303 inFIG. 3 ) by using the selected precoding method, and generate andtransmit the modulated signals. As described in this specification, thebase station or AP may perform phase change.

At this time, the data that is used by the terminal #p to notify thebase station or AP “whether modulated signals can be demodulated whenthe base station or AP performs any of the multiple precodingoperations” corresponds to the data 5301 about “supported precodingmethods”.

For example, it is assumed that, when the base station or AP generatesmodulated signals of multiple streams for the terminal #p, there is apossibility that precoding using the precoding matrix in Expression (33)or Expression (34) is supported as a precoding method #A, for example,and precoding using the precoding matrix in which θ=π/4 radians inExpression (15) or Expression (16) is supported as a precoding method#B, for example.

It is assumed that, when the base station or AP generates modulatedsignals of multiple streams for the terminal #p, the base station or APselects either of the precoding method #A and the precoding method #B asa precoding method, performs precoding (weight combining) by using theselected precoding method, and transmits the modulated signals.

At this time, the terminal #p transmits a modulated signal including“information indicating whether or not the terminal #p is able toreceive multiple modulated signals, demodulate the modulated signals,and obtain data when the base station or AP transmits the multiplemodulated signals to the terminal #p by using the precoding method #A”and “information indicating whether or not the terminal #p is able toreceive multiple modulated signals, demodulate the modulated signals,and obtain data when the base station or AP transmits the multiplemodulated signals to the terminal #p by using the precoding method #B”.By receiving this modulated signal, the base station or AP is able tolearn “whether the terminal #p as a communication partner supports theprecoding method #A and the precoding method #B and is able todemodulate the modulated signals”.

For example, the data 5301 about “supported precoding methods” in FIG.71 included in the reception capability notification symbol 2702transmitted by the terminal #p is configured as follows.

It is assumed that the data 5301 about “supported precoding methods” ismade up of 2 bits, bit m0 and bit m1. The terminal #p transmits bit m0and bit m1 as the data 5301 about “supported precoding methods” to thebase station or AP as a communication partner.

For example, in a case where the terminal #p is able to receive anddemodulate (support demodulation) “a modulated signal generated by thebase station or AP by using the precoding method #A”, m0=1 is set, andbit m0 is transmitted as a part of the data 5301 about “supportedprecoding methods” to the base station or AP as a communication partner.

In a case where the terminal #p is able to receive but unable todemodulate “a modulated signal generated by the base station or AP byusing the precoding method #A”, m0=0 is set, and bit m0 is transmittedas a part of the data 5301 about “supported precoding methods” to thebase station or AP as a communication partner.

For example, in a case where the terminal #p is able to receive anddemodulate (support demodulation) “a modulated signal generated by thebase station or AP by using the precoding method #B”, m1=1 is set, andbit m1 is transmitted as a part of the data 5301 about “supportedprecoding methods” to the base station or AP as a communication partner.

In a case where the terminal #p is able to receive but unable todemodulate “a modulated signal generated by the base station or AP byusing the precoding method #B”, m1=0 is set, and bit m1 is transmittedas a part of the data 5301 about “supported precoding methods” to thebase station or AP as a communication partner.

Next, specific operation examples will be described below by using firstto fifth examples.

First Example

As the first example, it is assumed that the reception apparatus of theterminal #p has the configuration illustrated in FIG. 19 and thereception apparatus of the terminal #p supports the following, forexample.

For example, the reception of “communication scheme #A” and“communication scheme #B” described in the third embodiment issupported.

In “communication scheme #B”, if the communication partner transmitsmodulated signals of multiple streams to the terminal #p, the terminal#p supports the reception of the modulated signals. In “communicationscheme #A” and “communication scheme #B”, if the communication partnertransmits a modulated signal of a single stream to the terminal #p, theterminal #p supports the reception of the modulated signal.

In a case where the communication partner performs phase change whentransmitting modulated signals of multiple streams to the terminal #p,the terminal #p supports the reception of the modulated signals.

The single-carrier scheme and the OFDM scheme are supported.

The decoding of “error-correcting coding scheme #C” and the decoding of“error-correcting coding scheme #D” are supported as theerror-correcting coding scheme.

The reception of “precoding method #A” and the reception of “precodingmethod #B” described above are supported.

Thus, the terminal #p having the configuration in FIG. 19 and supportingthe above generates the reception capability notification symbol 2702having the configuration illustrated in FIG. 71 on the basis of therules described in the third embodiment and the description of thepresent embodiment, and transmits the reception capability notificationsymbol 2702 in accordance with the procedure in FIG. 27 , for example.

At this time, the terminal #p generates the reception capabilitynotification symbol 2702 having the configuration illustrated in FIG. 71in the transmission apparatus 3403 in FIG. 34 , for example, and thetransmission apparatus 3403 in FIG. 34 transmits the receptioncapability notification symbol 2702 having the configuration illustratedin FIG. 71 in accordance with the procedure in FIG. 27 .

In the case of the first example, the terminal #p supports the receptionof “precoding method #A” and the reception of “precoding method #B”, andthus bit m0 is set to 1 and bit m1 is set to 1 in the data 5301 about“supported precoding methods”.

The signal processor 155 of the base station (AP) in FIG. 22 obtains thebaseband signal group 154 including the reception capabilitynotification symbol 2702 transmitted by the terminal #p, through thereception antenna group 151 and the radio section group 153.Subsequently, the signal processor 155 of the base station (AP) in FIG.22 extracts the data included in the reception capability notificationsymbol 2702 and learns, from the data 3001 about “supported schemes”,that the terminal #p supports “communication scheme #A” and“communication scheme #B”.

In addition, the signal processor 155 of the base station (AP) learns,from the data 2901 about “support/not support reception for multiplestreams” in FIG. 71 , that “if the communication partner transmitsmodulated signals of multiple streams to the terminal #p, the terminal#p supports the reception of the modulated signals”, and “if thecommunication partner in “communication scheme #A” and “communicationscheme #B” transmits a modulated signal of a single stream to theterminal #p, the terminal #p supports the reception of the modulatedsignal“.

In addition, the signal processor 155 of the base station (AP) learns,from the data 2801 about “support/not support demodulation of modulatedsignal with phase change” in FIG. 71 , that the terminal #p “supportsphase change demodulation”.

The signal processor 155 of the base station (AP) learns, from the data3002 about “support/not support multi-carrier scheme” in FIG. 71 , that“the terminal #p supports “single-carrier scheme” and “OFDM scheme”.

The signal processor 155 of the base station (AP) learns, from the data3003 about “supported error-correcting coding schemes” in FIG. 71 , thatthe terminal #p “supports the decoding of “error-correcting codingscheme #C” and the decoding of “error-correcting coding scheme #D””.

The signal processor 155 of the base station (AP) learns, from the data5301 about “supported precoding methods” in FIG. 71 , that the terminal#p “supports the reception of “precoding method #A” and the reception of“precoding method #B””.

Thus, the base station or AP appropriately generates and transmits amodulated signal that can be received by the terminal #p inconsideration of a communication scheme supported by the terminal #p anda communication environment, and accordingly the data transmissionefficiency in the system constituted by the base station or AP and theterminal #p can be increased.

Second Example

As the second example, it is assumed that the reception apparatus of theterminal #p has the configuration illustrated in FIG. 35 and thereception apparatus of the terminal #p supports the following, forexample.

For example, the reception of “communication scheme #A” and“communication scheme #B” described in the third embodiment issupported.

If the communication partner transmits modulated signals of multiplestreams to the terminal #p, the terminal #p does not support thereception of the modulated signals.

Thus, in a case where the communication partner performs phase changewhen transmitting modulated signals of multiple streams to the terminal#p, the terminal #p does not support the reception of the modulatedsignals.

The single-carrier scheme and the OFDM scheme are supported.

The decoding of “error-correcting coding scheme #C” and the decoding of“error-correcting coding scheme #D” are supported as theerror-correcting coding scheme.

The reception of “precoding method #A” and the reception of “precodingmethod #B” described above are not supported.

Thus, the terminal #p having the configuration in FIG. 35 and supportingthe above generates the reception capability notification symbol 2702having the configuration illustrated in FIG. 71 on the basis of therules described in the third embodiment and the description of thepresent embodiment, and transmits the reception capability notificationsymbol 2702 in accordance with the procedure in FIG. 27 , for example.

At this time, the terminal #p generates the reception capabilitynotification symbol 2702 having the configuration illustrated in FIG. 71in the transmission apparatus 3403 in FIG. 34 , for example, and thetransmission apparatus 3403 in FIG. 34 transmits the receptioncapability notification symbol 2702 having the configuration illustratedin FIG. 71 in accordance with the procedure in FIG. 27 .

The signal processor 155 of the base station (AP) in FIG. 22 obtains thebaseband signal group 154 including the reception capabilitynotification symbol 2702 transmitted by the terminal #p, through thereception antenna group 151 and the radio section group 153.Subsequently, the signal processor 155 of the base station (AP) in FIG.22 extracts the data included in the reception capability notificationsymbol 2702 and learns, from the data 3001 about “supported schemes”,that the terminal #p supports “communication scheme #A” and“communication scheme #B”.

In addition, the signal processor 155 of the base station (AP) learns,from the data 2901 about “support/not support reception for multiplestreams” in FIG. 71 , that “if the communication partner transmitsmodulated signals of multiple streams to the terminal #p, the terminal#p does not support the reception of the modulated signals”.

Thus, the signal processor 155 of the base station (AP) determines thatthe data 2801 about “support/not support demodulation of modulatedsignal with phase change” in FIG. 71 is invalid and determines not totransmit a modulated signal whose phase has been changed, and outputsthe control information 157 including this information.

In addition, the signal processor 155 of the base station (AP)determines that the data 5301 about “supported precoding methods” inFIG. 71 is invalid and determines not to transmit modulated signals formultiple streams, and outputs the control information 157 including thisinformation.

The signal processor 155 of the base station (AP) learns, from the data3002 about “support/not support multi-carrier scheme” in FIG. 71 , that“the terminal #p supports “single-carrier scheme” and “OFDM scheme”.

The signal processor 155 of the base station (AP) learns, from the data3003 about “supported error-correcting coding schemes” in FIG. 71 , thatthe terminal #p “supports the decoding of “error-correcting codingscheme #C” and the decoding of “error-correcting coding scheme #D””.

For example, the terminal #p has the configuration in FIG. 35 , and thusthe base station or AP performs the above-described operations so as notto transmit modulated signals for multiple streams to the terminal #p.Thus, the base station or AP is able to appropriately transmit amodulated signal that can be demodulated/decoded by the terminal #p.Accordingly, the data transmission efficiency in the system constitutedby the base station or AP and the terminal #p can be increased.

Third Example

As the third example, it is assumed that the reception apparatus of theterminal #p has the configuration illustrated in FIG. 19 and thereception apparatus of the terminal #p supports the following, forexample.

For example, the reception of “communication scheme #A” and“communication scheme #B” described in the third embodiment issupported.

In “communication scheme #B”, if the communication partner transmitsmodulated signals of multiple streams to the terminal #p, the terminal#p supports the reception of the modulated signals. In “communicationscheme #A” and “communication scheme #B”, if the communication partnertransmits a modulated signal of a single stream to the terminal #p, theterminal #p supports the reception of the modulated signal.

In a case where the communication partner performs phase change whentransmitting modulated signals of multiple streams to the terminal #p,the terminal #p supports the reception of the modulated signals.

The single-carrier scheme and the OFDM scheme are supported.

The decoding of “error-correcting coding scheme #C” and the decoding of“error-correcting coding scheme #D” are supported as theerror-correcting coding scheme.

The reception of “precoding method #A” described above is supported.That is, in the third example, the reception of “precoding method #B”described above is not supported.

Thus, the terminal #p having the configuration in FIG. 19 and supportingthe above generates the reception capability notification symbol 2702having the configuration illustrated in FIG. 71 on the basis of therules described in the third embodiment and the description of thepresent embodiment, and transmits the reception capability notificationsymbol 2702 in accordance with the procedure in FIG. 27 , for example.

At this time, the terminal #p generates the reception capabilitynotification symbol 2702 having the configuration illustrated in FIG. 71in the transmission apparatus 3403 in FIG. 34 , for example, and thetransmission apparatus 3403 in FIG. 34 transmits the receptioncapability notification symbol 2702 having the configuration illustratedin FIG. 71 in accordance with the procedure in FIG. 27 .

In the case of the third example, the terminal #p supports the receptionof “precoding method #A” and does not support the reception of“precoding method #B”, and thus bit m0 is set to 1 and the bit m1 is setto 0 in the data 5301 about “supported precoding methods”.

The signal processor 155 of the base station (AP) in FIG. 22 obtains thebaseband signal group 154 including the reception capabilitynotification symbol 2702 transmitted by the terminal #p, through thereception antenna group 151 and the radio section group 153.Subsequently, the signal processor 155 of the base station (AP) in FIG.22 extracts the data included in the reception capability notificationsymbol 2702 and learns, from the data 3001 about “supported schemes”,that the terminal #p supports “communication scheme #A” and“communication scheme #B”.

In addition, the signal processor 155 of the base station (AP) learns,from the data 2901 about “support/not support reception for multiplestreams” in FIG. 71 , that “if the communication partner transmitsmodulated signals of multiple streams to the terminal #p, the terminal#p supports the reception of the modulated signals”, and “if thecommunication partner in “communication scheme #A” and “communicationscheme #B” transmits a modulated signal of a single stream to theterminal #p, the terminal #p supports the reception of the modulatedsignal“.

In addition, the signal processor 155 of the base station (AP) learns,from the data 2801 about “support/not support demodulation of modulatedsignal with phase change” in FIG. 71 , that the terminal #p “supportsphase change demodulation”.

The signal processor 155 of the base station (AP) learns, from the data3002 about “support/not support multi-carrier scheme” in FIG. 71 , that“the terminal #p supports “single-carrier scheme” and “OFDM scheme”.

The signal processor 155 of the base station (AP) learns, from the data3003 about “supported error-correcting coding schemes” in FIG. 71 , thatthe terminal #p “supports the decoding of “error-correcting codingscheme #C” and the decoding of “error-correcting coding scheme #D””.

The signal processor 155 of the base station (AP) learns, from the data5301 about “supported precoding methods” in FIG. 71 , that the terminal#p “supports the reception of “precoding method #A””.

Thus, the base station or AP appropriately generates and transmits amodulated signal that can be received by the terminal #p inconsideration of a communication method supported by the terminal #p anda communication environment, and accordingly the data transmissionefficiency in the system constituted by the base station or AP and theterminal #p can be increased.

Fourth Example

As the fourth example, it is assumed that the reception apparatus of theterminal #p has the configuration illustrated in FIG. 19 and thereception apparatus of the terminal #p supports the following, forexample.

For example, the reception of “communication scheme #A” and“communication scheme #B” described in the third embodiment issupported.

In “communication scheme #B “, if the communication partner transmitsmodulated signals of multiple streams to the terminal #p, the terminal#p supports the reception of the modulated signals. In “communicationscheme #A” and “communication scheme #B”, if the communication partnertransmits a modulated signal of a single stream to the terminal #p, theterminal #p supports the reception of the modulated signal.

The single-carrier scheme is supported. In the single-carrier scheme,the base station as a communication partner does not support “performphase change in the case of modulated signals of multiple streams” anddoes not support “perform precoding”.

Thus, in a case where the communication partner performs phase changewhen transmitting modulated signals of multiple streams to the terminal#p, the terminal #p does not support the reception of the modulatedsignals.

The decoding of “error-correcting coding scheme #C” and the decoding of“error-correcting coding scheme #D” are supported as theerror-correcting coding scheme.

The reception of “precoding method #A” described above is supported.

Thus, the terminal #p having the configuration in FIG. 19 and supportingthe above generates the reception capability notification symbol 2702having the configuration illustrated in FIG. 71 on the basis of therules described in the third embodiment and the description of thepresent embodiment, and transmits the reception capability notificationsymbol 2702 in accordance with the procedure in FIG. 27 , for example.

At this time, the terminal #p generates the reception capabilitynotification symbol 2702 illustrated in FIG. 71 in the transmissionapparatus 3403 in FIG. 34 , for example, and the transmission apparatus3403 in FIG. 34 transmits the reception capability notification symbol2702 illustrated in FIG. 71 in accordance with the procedure in FIG. 27.

The signal processor 155 of the base station (AP) in FIG. 22 obtains thebaseband signal group 154 including the reception capabilitynotification symbol 2702 transmitted by the terminal #p, through thereception antenna group 151 and the radio section group 153.Subsequently, the signal processor 155 of the base station (AP) in FIG.22 extracts the data included in the reception capability notificationsymbol 2702 and learns, from the data 2901 about “support/not supportreception for multiple streams” in FIG. 71 , “if the communicationpartner transmits modulated signals of multiple streams to the terminal#p, the terminal #p supports the reception of the modulated signals” and“if the communication partner in “communication scheme #A” and“communication scheme #B” transmits a modulated signal of a singlestream to the terminal #p, the terminal #p supports the reception of themodulated signal“.

The signal processor 155 of the base station (AP) learns, from the data3002 about “support/not support multi-carrier scheme” in FIG. 71 , that“the terminal #p supports “single-carrier scheme””.

Thus, the signal processor 155 of the base station (AP) determines thatthe data 2801 about “support/not support demodulation of modulatedsignal with phase change” in FIG. 71 is invalid and determines not totransmit a modulated signal whose phase has been changed, and outputsthe control information 157 including this information.

In addition, the signal processor 155 of the base station (AP)determines that the data 5301 about “supported precoding methods” inFIG. 71 is invalid, and outputs the control information 157 indicating“precoding is not performed”.

The signal processor 155 of the base station (AP) learns, from the data3003 about “supported error-correcting coding schemes” in FIG. 71 , thatthe terminal #p “supports the decoding of “error-correcting codingscheme #C” and the decoding of “error-correcting coding scheme #D””.

Thus, the base station or AP appropriately generates and transmits amodulated signal that can be received by the terminal #p inconsideration of a communication method supported by the terminal #p anda communication environment, and accordingly the data transmissionefficiency in the system constituted by the base station or AP and theterminal #p can be increased.

Fifth Example

As the fifth example, it is assumed that the reception apparatus of theterminal #p has the configuration illustrated in FIG. 35 and thereception apparatus of the terminal #p supports the following, forexample.

For example, the reception of “communication scheme #A” described in thethird embodiment is supported.

Thus, if the communication partner transmits modulated signals ofmultiple streams to the terminal #p, the terminal #p does not supportthe reception of the modulated signals.

Thus, in a case where the communication partner performs phase changewhen transmitting modulated signals for multiple streams to the terminal#p, the terminal #p does not support the reception of the modulatedsignals.

Furthermore, if the communication partner transmits modulated signalsfor multiple streams generated by using “precoding method #A”, theterminal #p does not support the reception of the modulated signals.Also, if the communication partner transmits modulated signals formultiple streams generated by using “precoding method #B”, the terminal#p does not support the reception of the modulated signals.

Only the single-carrier scheme is supported.

Only the decoding of “error-correcting coding scheme #C” is supported asthe error-correcting coding scheme.

Thus, the terminal #p having the configuration in FIG. 35 and supportingthe above generates the reception capability notification symbol 2702having the configuration illustrated in FIG. 71 on the basis of therules described in the third embodiment and the description of thepresent embodiment, and transmits the reception capability notificationsymbol 2702 in accordance with the procedure in FIG. 27 , for example.

At this time, the terminal #p generates the reception capabilitynotification symbol 2702 having the configuration illustrated in FIG. 71in the transmission apparatus 3403 in FIG. 34 , for example, and thetransmission apparatus 3403 in FIG. 34 transmits the receptioncapability notification symbol 2702 having the configuration illustratedin FIG. 71 in accordance with the procedure in FIG. 27 .

The signal processor 155 of the base station (AP) in FIG. 22 obtains thebaseband signal group 154 including the reception capabilitynotification symbol 2702 transmitted by the terminal #p, through thereception antenna group 151 and the radio section group 153.Subsequently, the signal processor 155 of the base station (AP) in FIG.22 extracts the data included in the reception capability notificationsymbol 2702 and learns, from the data 3001 about “supported schemes”,that the terminal #p supports “communication scheme #A”.

Thus, since the data 2801 about “support/not support demodulation ofmodulated signal with phase change” in FIG. 71 is invalid and thecommunication scheme #A is supported, the signal processor 155 of thebase station (AP) determines not to transmit a modulated signal whosephase has been changed, and outputs the control information 157including this information. This is because the communication scheme #Adoes not support the transmission and reception of modulated signals formultiple streams.

In addition, since the data 2901 about “support/not support receptionfor multiple streams” in FIG. 71 is invalid and the communication scheme#A is supported, the signal processor 155 of the base station (AP)determines not to transmit modulated signals for multiple streams to theterminal #p, and outputs the control information 157 including thisinformation. This is because the communication scheme #A does notsupport the transmission and reception of modulated signals for multiplestreams.

In addition, since the data 5301 about “supported precoding methods” inFIG. 71 is invalid and the communication scheme #A is supported, thesignal processor 155 of the base station (AP) determines not to transmitmodulated signals for multiple streams, and outputs the controlinformation 157 including this information.

In addition, since the data 3003 about “supported error-correctingcoding schemes” in FIG. 71 is invalid and the communication scheme #A issupported, the signal processor 155 of the base station (AP) determinesto use “error-correcting coding scheme #C” and outputs the controlinformation 157 including this information. This is because thecommunication scheme #A supports “error-correcting coding scheme #C”.

For example, as in FIG. 35 , “communication scheme #A” is supported, andthus the base station or AP performs the above-described operations soas not to transmit modulated signals for multiple streams to theterminal #p. Thus, the base station or AP is able to appropriatelytransmit a modulated signal of “communication scheme #A”. As a result,the data transmission efficiency in the system constituted by the basestation or AP and the terminal #p can be increased.

As described above, the base station or AP obtains, from the terminal #pas a communication partner of the base station or AP, information abouta scheme in which the terminal #p supports the demodulation, and decidesthe number of modulated signals, the communication scheme of themodulated signals, the signal processing method of the modulatedsignals, and so forth on the basis of the information, thereby beingable to transmit a modulated signal that can be received by the terminal#p. As a result, the data transmission efficiency in the systemconstituted by the base station or AP and the terminal #p can beincreased.

At this time, for example, when the reception capability notificationsymbol 2702 is made up of multiple pieces of information as in FIG. 71 ,the base station or AP is able to easily determine whether theinformation included in the reception capability notification symbol2702 is valid or invalid. This results in an advantage of being able toquickly decide the scheme of modulated signals to be transmitted and/orthe signal processing method or the like.

The base station or AP transmits modulated signals to individualterminals #p by using preferable transmission methods on the basis ofthe details of information included in the reception capabilitynotification symbols 2702 transmitted by the individual terminals #p,and accordingly the data transmission efficiency increases.

In addition, the base station or AP in the present embodiment has theconfiguration in FIG. 1 and communicates with multiple terminals. Thereception capabilities (schemes in which demodulation is supported) ofthe multiple terminals as communication partners of the base station orAP in FIG. 1 may be identical to or different from one another. Each ofthe multiple terminals transmits a reception capability notificationsymbol including information about a scheme in which demodulation issupported. The base station or AP obtains, from each terminal, theinformation about a scheme in which demodulation is supported, anddecides the number of modulated signals, the communication scheme of themodulated signals, the signal processing method of the modulatedsignals, and so forth on the basis of the information, thereby beingable to transmit modulated signals that can be received by each terminalon the basis of the reception capability (scheme in which demodulationis supported) of each terminal. Accordingly, the data transmissionefficiency in the system constituted by the base station or AP and themultiple terminals can be increased. The base station or AP transmitsmodulated signals to the multiple terminals by using a certain timesection and certain frequencies. At this time, the base station or APtransmits one or more modulated signals to each terminal. Thus, eachterminal may transmit, for example, the reception capabilitynotification symbol as described above to the base station or AP.

The method for configuring the information of the reception capabilitynotification symbol described in the present embodiment is an example,and the method for configuring the information of the receptioncapability notification symbol is not limited thereto. In addition, thedescription of the present embodiment about the transmission procedureand transmission timing for transmitting the reception capabilitynotification symbol from the terminal #p to the base station or AP ismerely an example, and the transmission procedure and transmissiontiming are not limited thereto.

In addition, the present embodiment describes an example in which eachof multiple terminals transmits a reception capability notificationsymbol. The method for configuring the information of the receptioncapability notification symbol transmitted by the multiple terminals maybe different or identical among the terminals. Also, the transmissionprocedure and transmission timing for transmitting the receptioncapability notification symbol by the multiple terminals may bedifferent or identical among the terminals.

Fourth Supplement

In this specification, FIG. 35 illustrates an example of theconfiguration of the reception apparatus of the terminal #p as acommunication partner of the base station or AP in a case where thetransmission apparatus of the base station or AP transmits a modulatedsignal of a single stream, but the configuration of the terminal #p thatreceives the modulated signal of a single stream is not limited to FIG.35 . For example, the reception apparatus of the terminal #p may includemultiple reception antennas. For example, in FIG. 19 , in a case wherethe modulated signal u2 channel estimators 1905_2 and 1907_2 do notoperate, the channel estimator for one modulated signal operates, andthus a modulated signal of a single stream can be received even withthis configuration.

Thus, in the description of this specification, the operation of theembodiment described by using FIG. 35 can be achieved similarly with theabove-described configuration of the reception apparatus instead of theconfiguration in FIG. 19 , and also similar effects can be obtained.

Additionally, in this specification, the configurations in FIGS. 28, 29,30, and 71 have been described as examples of the configuration of thereception capability notification symbol transmitted by the terminal #p.At this time, an effect of the reception capability notification symbol“being made up of multiple pieces of information (multiple pieces ofdata)” has been described. Hereinafter, a description will be given of amethod for transmitting “multiple pieces of information (multiple piecesof data)” constituting the reception capability notification symboltransmitted by the terminal #p.

Example Configuration 1

In FIG. 30 , for example, among the data 2801 about “support/not supportdemodulation of modulated signal with phase change”, the data 2901 about“support/not support reception for multiple streams”, the data 3001about “supported schemes”, the data 3002 about “support/not supportmulti-carrier scheme”, and the data 3003 about “supportederror-correcting coding schemes”, at least two or more pieces of data(information) are transmitted by using the same frame or the samesubframe.

Example Configuration 2

In FIG. 71 , for example, among the data 2801 about “support/not supportdemodulation of modulated signal with phase change”, the data 2901 about“support/not support reception for multiple streams”, the data 3001about “supported schemes”, the data 3002 about “support/not supportmulti-carrier scheme”, the data 3003 about “supported error-correctingcoding schemes”, and the data 5301 about “supported precoding methods”,at least two or more pieces of data (information) are transmitted byusing the same frame or the same subframe.

Now, a “frame” and a “subframe” will be described.

FIG. 72 is a diagram illustrating an example of the configuration of aframe. In FIG. 72 , the horizontal axis indicates time. For example, inFIG. 72 , it is assumed that the frame includes a preamble 8001, controlinformation symbols 8002, and data symbols 8003. However, the frame neednot necessarily include all of the three items. For example, the framemay “at least include the preamble 8001”, “at least include the controlinformation symbols 8002”, “at least include the preamble 8001 and thedata symbols 8003”, “at least include the preamble 8001 and the controlinformation symbols 8002”, or “at least include the preamble 8001, thecontrol information symbols 8002, and the data symbols 8003”.

The terminal #p transmits the reception capability notification symbolby using any symbol among the preamble 8001, the control informationsymbols 8002, and the data symbols 8003.

FIG. 72 may be called a subframe. Alternatively, a term other than“frame” and “subframe” may be used.

By using the above-described method, the terminal #p transmits at leasttwo or more pieces of information included in the reception capabilitynotification symbol, and accordingly the effects described in the thirdembodiment, the fifth embodiment, the eleventh embodiment, and so forthcan be obtained.

Example Configuration 3

In FIG. 30 , for example, among the data 2801 about “support/not supportdemodulation of modulated signal with phase change”, the data 2901 about“support/not support reception for multiple streams”, the data 3001about “supported schemes”, the data 3002 about “support/not supportmulti-carrier scheme”, and the data 3003 about “supportederror-correcting coding schemes”, at least two or more pieces of data(information) are transmitted by using the same packet.

Example Configuration 4

In FIG. 71 , for example, among the data 2801 about “support/not supportdemodulation of modulated signal with phase change”, the data 2901 about“support/not support reception for multiple streams”, the data 3001about “supported schemes”, the data 3002 about “support/not supportmulti-carrier scheme”, the data 3003 about “supported error-correctingcoding schemes”, and the data 5301 about “supported precoding methods”,at least two or more pieces of data (information) are transmitted byusing the same packet.

The frame in FIG. 72 will be discussed. It is assumed that the frame “atleast includes the preamble 8001 and the data symbols 8003”, “at leastincludes the control information symbols 8002 and the data symbols8003”, or “at least includes the preamble 8001, the control informationsymbols 8002, and the data symbols 8003”.

At this time, there are two methods for transmitting the packet, forexample.

First Method:

The data symbols 8003 are made up of multiple packets. In this case, atleast two or more pieces of data (information) included in the receptioncapability notification symbol are transmitted by using the data symbols8003.

Second Method:

The packet is transmitted by the data symbols of multiple frames. Inthis case, at least two or more pieces of data (information) included inthe reception capability notification symbol are transmitted by usingmultiple frames.

The terminal #p transmits at least two or more pieces of data(information) included in the reception capability notification symbolby using the above-described methods, and accordingly the effectsdescribed in the third embodiment, the fifth embodiment, the eleventhembodiment, and so forth can be obtained.

The term “preamble” is used in FIG. 72 , but the term is not limitedthereto. It is assumed that “preamble” includes at least one or moresymbols or signals among “a symbol or signal used by the communicationpartner to detect a modulated signal”, “a symbol or signal used by thecommunication partner to perform channel estimation (propagationenvironment estimation)”, “a symbol or signal used by the communicationpartner to perform time synchronization”, “a symbol or signal used bythe communication partner to perform frequency synchronization”, and “asymbol or signal used by the communication partner to estimate frequencyoffset”.

The term “control information symbols” is used in FIG. 72 , but the termis not limited thereto. It is assumed that “control information symbols”are symbols including at least one or more pieces of information among“information about the error-correcting coding scheme for generatingdata symbols”, “information about the modulation scheme for generatingdata symbols”, “information about the number of symbols constituting thedata symbols”, “information about the method for transmitting datasymbols”, “information that needs to be transmitted to the communicationpartner other than data symbols”, and “information other than datasymbols”.

The order in which the preamble 8001, the control information symbols8002, and the data symbols 8003 are transmitted, that is, the frameconfiguration method, is not limited to that in FIG. 72 .

In the third embodiment, the fifth embodiment, the eleventh embodiment,and so forth, the terminal #p transmits the reception capabilitynotification symbol, and the communication partner of the terminal #p isthe base station or AP, but the embodiments are not limited thereto. Forexample, the communication partner of the base station or AP may be theterminal #p, and the base station or AP may transmit the receptioncapability notification symbol to the terminal #p as the communicationpartner. Alternatively, the communication partner of the terminal #p maybe another terminal, and the terminal #p may transmit the receptioncapability notification symbol to the other terminal as thecommunication partner. Alternatively, the communication partner of thebase station or AP may be another base station or AP, and the basestation or AP may transmit the reception capability notification symbolto the other base station or AP as the communication partner.

Sixteenth Embodiment

In the first to fifteenth embodiments, the first to fourth supplements,and so forth, in the phase changer 305B, the phase changer 305A, thephase changer 309A, the phase changer 3801B, and the phase changer 3801Ain FIGS. 3, 4, 26, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 52 , andso forth, a description is given by using, for example, Expression (2),Expression (50), and so forth. In addition, a description is given thatthe value of a phase change value need not be based on these expressionsand “it is sufficient to change the phase periodically or regularly”.

In the present embodiment, a description will be given of anotherexample of “it is sufficient to change the phase periodically orregularly”. FIG. 73 is a diagram illustrating an example of carriergroups of modulated signals transmitted by the base station or AP. InFIG. 73 , the horizontal axis indicates frequency (carrier), and thevertical axis indicates time.

For example, as in FIG. 73 , a first carrier group made up of carrier #1to carrier #5, a second carrier group made up of carrier #6 to carrier#10, a third carrier group made up of carrier #11 to carrier #15, afourth carrier group made up of carrier #16 to carrier #20, and a fifthcarrier group made up of carrier #21 to carrier #25 are considered. Itis assumed that the base station or AP uses the first carrier group, thesecond carrier group, the third carrier group, the fourth carrier group,and the fifth carrier group to transmit data to a certain terminal(certain user) (terminal #p).

The phase change value used by the phase changer 305A is Yp(i), thephase change value used by the phase changer 305B is yp(i), the phasechange value used by the phase changer 3801A is Vp(i), and the phasechange value used by the phase changer 3801B is vp(i) in FIGS. 3, 4, 26,38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 52 , and so forth.

At this time, it is assumed that the phase changer 305A performs phasechange on the symbols belonging to the first carrier group in FIG. 73 byusing e^(j×E1) as the phase change value Yp(i). It is assumed that E1 isa real number. For example, E1 is 0 (radians)≤E1<2×π (radians).

Also, it is assumed that the phase changer 305A performs phase change onthe symbols belonging to the second carrier group in FIG. 73 by usinge^(j×E2) as the phase change value Yp(i). It is assumed that E2 is areal number. For example, E2 is 0 (radians)≤E2<2×π (radians).

It is assumed that the phase changer 305A performs phase change on thesymbols belonging to the third carrier group in FIG. 73 by usinge^(j×E3) as the phase change value Yp(i). It is assumed that E3 is areal number. For example, E3 is 0 (radians)≤E3<2×π (radians).

It is assumed that the phase changer 305A performs phase change on thesymbols belonging to the fourth carrier group in FIG. 73 by usinge^(j×E4) as the phase change value Yp(i). It is assumed that E4 is areal number. For example, E4 is 0 (radians)≤E4<2×π (radians).

It is assumed that the phase changer 305A performs phase change on thesymbols belonging to the fifth carrier group in FIG. 73 by usinge^(j×E5) as the phase change value Yp(i). It is assumed that E5 is areal number. For example, E5 is 0 (radians)≤E5<2×π (radians).

As a first example, there is a method in which “E1≠E2 and E1≠E3 andE1≠E4 and E1≠E5 and E2≠E3 and E2≠E4 and E2≠E5 and E3≠E4 and E3≠E5 andE4≠E5” holds. When generalized, this is a method in which “x is aninteger equal to or greater than 1, y is an integer equal to or greaterthan 1, x≠y holds, and Ex≠Ey holds in all x and all y satisfying theseconditions”.

As a second example, there is a method in which “E1≠E2 or E1≠E3 or E1≠E4or E1≠E5 or E2≠E3 or E2≠E4 or E2≠E5 or E3≠E4 or E3≠E5 or E4≠E5” holds.When generalized, this is a method in which “there is a set of x and yin which x is an integer equal to or greater than 1, y is an integerequal to or greater than 1, x≠y holds, and Ex≠Ey holds”.

In addition, it is assumed that the phase changer 305B performs phasechange on the symbols belonging to the first carrier group in FIG. 73 byusing e^(j×F1) as the phase change value yp(i). It is assumed that F1 isa real number. For example, F1 is 0 (radians)≤F1<2×π (radians).

Also, it is assumed that the phase changer 305B performs phase change onthe symbols belonging to the second carrier group in FIG. 73 by usinge^(j×F2) as the phase change value yp(i). It is assumed that F2 is areal number. For example, F2 is 0 (radians)≤F2<2×π (radians).

It is assumed that the phase changer 305B performs phase change on thesymbols belonging to the third carrier group in FIG. 73 by usinge^(j×F3) as the phase change value yp(i). It is assumed that F3 is areal number. For example, F3 is 0 (radians)≤F3<2×π (radians).

It is assumed that the phase changer 305B performs phase change on thesymbols belonging to the fourth carrier group in FIG. 73 by usinge^(j×F4) as the phase change value yp(i). It is assumed that F4 is areal number. For example, F4 is 0 (radians)≥F4<2×π (radians).

It is assumed that the phase changer 305B performs phase change on thesymbols belonging to the fifth carrier group in FIG. 73 by usinge^(j×F5) as the phase change value yp(i). It is assumed that F5 is areal number. For example, F5 is 0 (radians)≤F5<2×π (radians).

As a first example, there is a method in which “F1≠F2 and F1≠F3 andF1≠F4 and F1≠F5 and F2≠F3 and F2≠F4 and F2≠F5 and F3≠F4 and F3≠F5 andF4≠F5” holds. When generalized, this is a method in which “x is aninteger equal to or greater than 1, y is an integer equal to or greaterthan 1, x≠y holds, and Fx≠Fy holds in all x and all y satisfying theseconditions”.

As a second example, there is a method in which “F1≠F2 or F1≠F3 or F1≠F4or F1≠F5 or F2≠F3 or F2≠F4 or F2≠F5 or F3≠F4 or F3≠F5 or F4≠F5” holds.When generalized, this is a method in which “there is a set of x and yin which x is an integer equal to or greater than 1, y is an integerequal to or greater than 1, x≠y holds, and Fx≠Fy holds”.

In addition, it is assumed that the phase changer 3801A performs phasechange on the symbols belonging to the first carrier group in FIG. 73 byusing e^(j×G1) as the phase change value Vp(i). It is assumed that G1 isa real number. For example, G1 is 0 (radians)≤G1<2×π (radians).

Also, it is assumed that the phase changer 3801A performs phase changeon the symbols belonging to the second carrier group in FIG. 73 by usinge^(j×G2) as the phase change value Vp(i). It is assumed that G2 is areal number. For example, G2 is 0 (radians)≤G2<2×π (radians).

It is assumed that the phase changer 3801A performs phase change on thesymbols belonging to the third carrier group in FIG. 73 by usinge^(j×G3) as the phase change value Vp(i). It is assumed that G3 is areal number. For example, G3 is 0 (radians)≤G3<2×π (radians).

It is assumed that the phase changer 3801A performs phase change on thesymbols belonging to the fourth carrier group in FIG. 73 by usinge^(j×G4) as the phase change value Vp(i). It is assumed that G4 is areal number. For example, G4 is 0 (radians)≤G4<2×π (radians).

It is assumed that the phase changer 3801A performs phase change on thesymbols belonging to the fifth carrier group in FIG. 73 by usinge^(j×G5) as the phase change value Vp(i). It is assumed that G5 is areal number. For example, G5 is 0 (radians)≤G5<2×π (radians).

As a first example, there is a method in which “G1≠G2 and G1≠G3 andG1≠G4 and G1≠G5 and G2≠G3 and G2≠G4 and G2≠G5 and G3≠G4 and G3≠G5 andG4≠G5” holds. When generalized, this is a method in which “x is aninteger equal to or greater than 1, y is an integer equal to or greaterthan 1, x≠y holds, and Gx≠Gy holds in all x and all y satisfying theseconditions”.

As a second example, there is a method in which “G1≠G2 or G1≠G3 or G1≠G4or G1≠G5 or G2≠G3 or G2≠G4 or G2≠G5 or G3≠G4 or G3≠G5 or G4≠G5” holds.When generalized, this is a method in which “there is a set of x and yin which x is an integer equal to or greater than 1, y is an integerequal to or greater than 1, x≠y holds, and Gx≠Gy holds”.

In addition, it is assumed that the phase changer 3801B performs phasechange on the symbols belonging to the first carrier group in FIG. 73 byusing e^(j×H1) as the phase change value vp(i). It is assumed that H1 isa real number. For example, H1 is 0 (radians)≤H1<2×π (radians).

Also, it is assumed that the phase changer 3801B performs phase changeon the symbols belonging to the second carrier group in FIG. 73 by usinge^(j×H2) as the phase change value vp(i). It is assumed that H2 is areal number. For example, H2 is 0 (radians)≤H2<2×π (radians).

It is assumed that the phase changer 3801B performs phase change on thesymbols belonging to the third carrier group in FIG. 73 by usinge^(j×H3) as the phase change value vp(i). It is assumed that H3 is areal number. For example, H3 is 0 (radians)≤H3<2×π (radians).

It is assumed that the phase changer 3801B performs phase change on thesymbols belonging to the fourth carrier group in FIG. 73 by usinge^(j×H4) as the phase change value vp(i). It is assumed that H4 is areal number. For example, H4 is 0 (radians)≤H4<2×π (radians).

It is assumed that the phase changer 3801B performs phase change on thesymbols belonging to the fifth carrier group in FIG. 73 by usinge^(j×H5) as the phase change value vp(i). It is assumed that H5 is areal number. For example, H5 is 0 (radians)≤H5<2×π (radians).

As a first example, there is a method in which “H1≠H2 and H1≠H3 andH1≠H4 and H1≠H5 and H2≠H3 and H2≠H4 and H2≠H5 and H3≠H4 and H3≠H5 andH4≠H5” holds. When generalized, this is a method in which “x is aninteger equal to or greater than 1, y is an integer equal to or greaterthan 1, x≠y holds, and Hx≠Hy holds in all x and all y satisfying theseconditions”.

As a second example, there is a method in which “H1≠H2 or H1≠H3 or H1≠H4or H1≠H5 or H2≠H3 or H2≠H4 or H2≠H5 or H3≠H4 or H3≠H5 or H4≠H5” holds.When generalized, this is a method in which “there is a set of x and yin which x is an integer equal to or greater than 1, y is an integerequal to or greater than 1, x≠y holds, and Hx≠Hy holds”.

FIG. 73 illustrates the first carrier group to the fifth carrier group,but the number of carrier groups is not limited to five. The embodimentcan be carried out similarly when two or more carrier groups exist.Alternatively, the number of carrier groups may be set to one. Forexample, one or more carrier groups may exist on the basis of acommunication situation, feedback information from a terminal, or thelike. When there is one carrier group, phase change is not performed. Asin the example in FIG. 73 , each carrier group may be set to a value ofa fixed number.

In addition, each of the first carrier group, the second carrier group,the third carrier group, the fourth carrier group, and the fifth carriergroup has a configuration including five carriers, but the configurationis not limited thereto. Thus, it is sufficient for each carrier group toinclude one or more carriers. Among different carrier groups, the numberof carriers included may be identical or different. For example, in FIG.73 , the number of carriers included in the first carrier group is five,and the number of carriers included in the second carrier group is alsofive (identical). For another example, in FIG. 73 , the number ofcarriers included in the first carrier group may be five, and the numberof carriers included in the second carrier group may be different, forexample, ten.

FIG. 74 is a diagram illustrating an example of carrier groups ofmodulated signals transmitted by the base station or AP, different fromthe example in FIG. 73 . In FIG. 74 , the horizontal axis indicatesfrequency (carrier), and the vertical axis indicates time.

A first carrier group_1 is made up of carrier #1 to carrier #5 and time$1 to time $3. A second carrier group_1 is made up of carrier #6 tocarrier #10 and time $1 to time $3. A third carrier group_1 is made upof carrier #11 to carrier #15 and time $1 to time $3. A fourth carriergroup_1 is made up of carrier #16 to carrier #20 and time $1 to time $3.A fifth carrier group_1 is made up of carrier #21 to carrier #25 andtime $1 to time $3.

A first carrier group_2 is made up of carrier #1 to carrier #5 and time$4 to time $9. A second carrier group_2 is made up of carrier #6 tocarrier #10 and time $4 to time $9. A third carrier group_2 is made upof carrier #11 to carrier #15 and time $4 to time $9. A fourth carriergroup_2 is made up of carrier #16 to carrier #20 and time $4 to time $9.A fifth carrier group_2 is made up of carrier #21 to carrier #25 andtime $4 to time $9.

A first carrier group_3 is made up of carrier #1 to carrier #25 and time$10 to time $11.

A first carrier group_4 is made up of carrier #1 to carrier #10 and time$12 to time $14. A second carrier group_4 is made up of carrier #11 tocarrier #15 and time $12 to time $14. A third carrier group_4 is made upof carrier #16 to carrier #25 and time $12 to time $14.

In FIG. 74 , it is assumed that the base station or AP uses carrier #1to carrier #25 and time $1 to time $14 to transmit data to a certainterminal (certain user) (terminal #p).

The phase change value used by the phase changer 305A is Yp(i), thephase change value used by the phase changer 305B is yp(i), the phasechange value used by the phase changer 3801A is Vp(i), and the phasechange value used by the phase changer 3801B is vp(i) in FIGS. 3, 4, 26,38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 52 , and so forth.

At this time, it is assumed that the phase changer 305A performs phasechange on the symbols belonging to the first carrier group_1 in FIG. 74by using e^(j×E11) as the phase change value Yp(i). It is assumed thatE11 is a real number. For example, E11 is 0 (radians)≤E11<2×π (radians).

Also, it is assumed that the phase changer 305A performs phase change onthe symbols belonging to the second carrier group_1 in FIG. 74 by usinge^(j×E21) as the phase change value Yp(i). It is assumed that E21 is areal number. For example, E21 is 0 (radians)≤E21<2×π (radians).

It is assumed that the phase changer 305A performs phase change on thesymbols belonging to the third carrier group_1 in FIG. 74 by usinge^(j×E31) as the phase change value Yp(i). It is assumed that E31 is areal number. For example, E31 is 0 (radians)≤E31<2×π (radians).

It is assumed that the phase changer 305A performs phase change on thesymbols belonging to the fourth carrier group_1 in FIG. 74 by usinge^(j×E41) as the phase change value Yp(i). It is assumed that E41 is areal number. For example, E41 is 0 (radians)≤E41<2×π (radians).

It is assumed that the phase changer 305A performs phase change on thesymbols belonging to the fifth carrier group_1 in FIG. 74 by usinge^(j×E51) as the phase change value Yp(i). It is assumed that E51 is areal number. For example, E51 is 0 (radians)≤E51<2×π (radians).

As a first example, there is a method in which “E11≠E21 and E11≠E31 andE11≠E41 and E11≠E51 and E21≠E31 and E21≠E41 and E21≠E51 and E31≠E41 andE31≠E51 and E41≠E51” holds. When generalized, this is a method in which“x is an integer equal to or greater than 1, y is an integer equal to orgreater than 1, x≠y holds, and Ex1≠Ey1 holds in all x and all ysatisfying these conditions”.

As a second example, there is a method in which “E11≠E21 or E11≠E31, orE11≠E41 or E11≠E51 or E21≠E31 or E21≠E41 or E21≠E51 or E31≠E41 orE31≠E51 or E41≠E51” holds. When generalized, this is a method in which“there is a set of x and y in which x is an integer equal to or greaterthan 1, y is an integer equal to or greater than 1, x≠y holds, andEx1≠Ey1 holds”.

In addition, it is assumed that the phase changer 305B performs phasechange on the symbols belonging to the first carrier group_1 in FIG. 74by using e^(j×F11) as the phase change value yp(i). It is assumed thatF11 is a real number. For example, F11 is 0 (radians)≤F11<2×π (radians).

Also, it is assumed that the phase changer 305B performs phase change onthe symbols belonging to the second carrier group_1 in FIG. 74 by usinge^(j×F21) as the phase change value yp(i). It is assumed that F21 is areal number. For example, F21 is 0 (radians)≤F21<2×π (radians).

It is assumed that the phase changer 305B performs phase change on thesymbols belonging to the third carrier group_1 in FIG. 74 by usinge^(j×F31) as the phase change value yp(i). It is assumed that F31 is areal number. For example, F31 is 0 (radians)≤F31<2×π (radians).

It is assumed that the phase changer 305B performs phase change on thesymbols belonging to the fourth carrier group_1 in FIG. 74 by usinge^(j×F41) as the phase change value yp(i). It is assumed that F41 is areal number. For example, F41 is 0 (radians)≤F41<2×π (radians).

It is assumed that the phase changer 305B performs phase change on thesymbols belonging to the fifth carrier group_1 in FIG. 74 by usinge^(j×F51) as the phase change value yp(i). It is assumed that F51 is areal number. For example, F51 is 0 (radians)≤F51<2×π (radians).

As a first example, there is a method in which “F11≠F21 and F11≠F31 andF11≠F41 and F11≠F51 and F21≠F31 and F21≠F41 and F21≠F51 and F31≠F41 andF31≠F51 and F41≠F51” holds. When generalized, this is a method in which“x is an integer equal to or greater than 1, y is an integer equal to orgreater than 1, x≠y holds, and Fx1≠Fy1 holds in all x and all ysatisfying these conditions”.

As a second example, there is a method in which “F11≠F21 or F11≠F31 orF11≠F41 or F11≠F51 or F21≠F31 or F21≠F41 or F21≠F51 or F31≠F41 orF31≠F51 or F41≠F51” holds. When generalized, this is a method in which“there is a set of x and y in which x is an integer equal to or greaterthan 1, y is an integer equal to or greater than 1, x≠y holds, andFx1≠Fy1 holds”.

In addition, it is assumed that the phase changer 3801A performs phasechange on the symbols belonging to the first carrier group_1 in FIG. 74by using e^(j×G11) as the phase change value Vp(i). It is assumed thatG11 is a real number. For example, G11 is 0 (radians)≤G11<2×π (radians).

Also, it is assumed that the phase changer 3801A performs phase changeon the symbols belonging to the second carrier group_1 in FIG. 74 byusing e^(j×G21) as the phase change value Vp(i). It is assumed that G21is a real number. For example, G21 is 0 (radians)≤G21<2×π (radians).

It is assumed that the phase changer 3801A performs phase change on thesymbols belonging to the third carrier group_1 in FIG. 74 by usinge^(j×G31) as the phase change value Vp(i). It is assumed that G31 is areal number. For example, G31 is 0 (radians)≤G31<2×π (radians).

It is assumed that the phase changer 3801A performs phase change on thesymbols belonging to the fourth carrier group_1 in FIG. 74 by usinge^(j×G41) as the phase change value Vp(i). It is assumed that G41 is areal number. For example, G41 is 0 (radians)≤G41<2×π (radians).

It is assumed that the phase changer 3801A performs phase change on thesymbols belonging to the fifth carrier group_1 in FIG. 74 by usinge^(j×G51) as the phase change value Vp(i). It is assumed that G51 is areal number. For example, G51 is 0 (radians)≤G51<2×π (radians).

For example, as a first example, there is a method in which “G11≠G21 andG11≠G31 and G11≠G41 and G11≠G51 and G21≠G31 and G21≠G41 and G21≠G51 andG31≠G41 and G31≠G51 and G41≠G51” holds. When generalized, this is amethod in which “x is an integer equal to or greater than 1, y is aninteger equal to or greater than 1, x≠y holds, and Gx1≠Gy1 holds in allx and all y satisfying these conditions”.

As a second example, there is a method in which “G11≠G21 or G11≠G31 orG11≠G41 or G11≠G51 or G21≠G31 or G21≠G41 or G21≠G51 or G31≠G41 orG31≠G51 or G41≠G51” holds. When generalized, this is a method in which“there is a set of x and y in which x is an integer equal to or greaterthan 1, y is an integer equal to or greater than 1, x≠y holds, andGx1≠Gy1 holds”.

In addition, it is assumed that the phase changer 3801B performs phasechange on the symbols belonging to the first carrier group_1 in FIG. 74by using e^(j×H11) as the phase change value vp(i). It is assumed thatH11 is a real number. For example, H11 is 0 (radians)≤H11<2×π (radians).

Also, it is assumed that the phase changer 3801B performs phase changeon the symbols belonging to the second carrier group_1 in FIG. 74 byusing e^(j×H21) as the phase change value vp(i). It is assumed that H21is a real number. For example, H21 is 0 (radians)≤H21<2×π (radians).

It is assumed that the phase changer 3801B performs phase change on thesymbols belonging to the third carrier group_1 in FIG. 74 by usinge^(j×H31) as the phase change value vp(i). It is assumed that H31 is areal number. For example, H31 is 0 (radians)≤H31<2×π (radians).

It is assumed that the phase changer 3801B performs phase change on thesymbols belonging to the fourth carrier group_1 in FIG. 74 by usinge^(j×H41) as the phase change value vp(i). It is assumed that H41 is areal number. For example, H41 is 0 (radians)≤H41<2×π (radians).

It is assumed that the phase changer 3801B performs phase change on thesymbols belonging to the fifth carrier group_1 in FIG. 74 by usinge^(j×H51) as the phase change value vp(i). It is assumed that H51 is areal number. For example, H51 is 0 (radians)≤H51<2×π (radians).

As a first example, there is a method in which “H11≠H21 and H11≠H31 andH11≠H41 and H11≠H51 and H21≠H31 and H21≠H41 and H21≠H51 and H31≠H41 andH31≠H51 and H41≠H51” holds. When generalized, this is a method in which“x is an integer equal to or greater than 1, y is an integer equal to orgreater than 1, x≠y holds, and Hx1≠Hy1 holds in all x and all ysatisfying these conditions”.

As a second example, there is a method in which “H11≠H21 or H11≠H31 orH11≠H41 or H11≠H51 or H21≠H31 or H21≠H41 or H21≠H51 or H31≠H41 orH31≠H51 or H41≠H51” holds. When generalized, this is a method in which“there is a set of x and y in which x is an integer equal to or greaterthan 1, y is an integer equal to or greater than 1, x≠y holds, andHx1≠Hy1 holds”.

It is assumed that the phase changer 305A performs phase change on thesymbols belonging to the first carrier group_2 in FIG. 74 by usinge^(j×E12) as the phase change value Yp(i). It is assumed that E12 is areal number. For example, E12 is 0 (radians)≤E12<2×π (radians).

Also, it is assumed that the phase changer 305A performs phase change onthe symbols belonging to the second carrier group_2 in FIG. 74 by usinge^(j×E22) as the phase change value Yp(i). It is assumed that E22 is areal number. For example, E22 is 0 (radians)≤E22<2×π (radians).

It is assumed that the phase changer 305A performs phase change on thesymbols belonging to the third carrier group_2 in FIG. 74 by usinge^(j×E32) as the phase change value Yp(i). It is assumed that E32 is areal number. For example, E32 is 0 (radians)≤E32<2×π (radians).

It is assumed that the phase changer 305A performs phase change on thesymbols belonging to the fourth carrier group_2 in FIG. 74 by usinge^(j×E42) as the phase change value Yp(i). It is assumed that E42 is areal number. For example, E42 is 0 (radians)≤E42<2×π (radians).

It is assumed that the phase changer 305A performs phase change on thesymbols belonging to the fifth carrier group_2 in FIG. 74 by usinge^(j×E52) as the phase change value Yp(i). It is assumed that E52 is areal number. For example, E52 is 0 (radians)≤E52<2×π (radians).

As a first example, there is a method in which “E12≠E22 and E12≠E32 andE12≠E42 and E12≠E52 and E22≠E32 and E22≠E42 and E22≠E52 and E32≠E42 andE32≠E52 and E42≠E52” holds. When generalized, this is a method in which“x is an integer equal to or greater than 1, y is an integer equal to orgreater than 1, x≠y holds, and Ex2≠Ey2 holds in all x and all ysatisfying these conditions”.

As a second example, there is a method in which “E12≠E22 or E12≠E32 orE12≠E42 or E12≠E52 or E22≠E32 or E22≠E42 or E22≠E52 or E32≠E42 orE32≠E52 or E42≠E52” holds. When generalized, this is a method in which“there is a set of x and y in which x is an integer equal to or greaterthan 1, y is an integer equal to or greater than 1, x≠y holds, andEx2≠Ey2 holds”.

In addition, it is assumed that the phase changer 305B performs phasechange on the symbols belonging to the first carrier group_2 in FIG. 74by using e^(j×F12) as the phase change value yp(i). It is assumed thatF12 is a real number. For example, F12 is 0 (radians)≤F12<2×π (radians).

Also, it is assumed that the phase changer 305B performs phase change onthe symbols belonging to the second carrier group_2 in FIG. 74 by usinge^(j×F22) as the phase change value yp(i). It is assumed that F22 is areal number. For example, F22 is 0 (radians)≤F22<2×π (radians).

It is assumed that the phase changer 305B performs phase change on thesymbols belonging to the third carrier group_2 in FIG. 74 by usinge^(j×F32) as the phase change value yp(i). It is assumed that F32 is areal number. For example, F32 is 0 (radians)≤F32<2×π (radians).

It is assumed that the phase changer 305B performs phase change on thesymbols belonging to the fourth carrier group_2 in FIG. 74 by usinge^(j×F42) as the phase change value yp(i). It is assumed that F42 is areal number. For example, F42 is 0 (radians)≤F42<2×π (radians).

It is assumed that the phase changer 305B performs phase change on thesymbols belonging to the fifth carrier group_2 in FIG. 74 by usinge^(j×F52) as the phase change value yp(i). It is assumed that F52 is areal number. For example, F52 is 0 (radians)≤F52<2×π (radians).

As a first example, there is a method in which “F12≠F22 and F12≠F32 andF12≠F42 and F12≠F52 and F22≠F32 and F22≠F42 and F22≠F52 and F32≠F42 andF32≠F52 and F42≠F52” holds. When generalized, this is a method in which“x is an integer equal to or greater than 1, y is an integer equal to orgreater than 1, x≠y holds, and Fx2≠Fy2 holds in all x and all ysatisfying these conditions”.

As a second example, there is a method in which “F12≠F22 or F12≠F32 orF12≠F42 or F12≠F52 or F22≠F32 or F22≠F42 or F22≠F52 or F32≠F42 orF32≠F52 or F42≠F52” holds. When generalized, this is a method in which“there is a set of x and y in which x is an integer equal to or greaterthan 1, y is an integer equal to or greater than 1, x≠y holds, andFx2≠Fy2 holds”.

In addition, it is assumed that the phase changer 3801A performs phasechange on the symbols belonging to the first carrier group_2 in FIG. 74by using e^(j×G12) as the phase change value Vp(i). It is assumed thatG12 is a real number. For example, G12 is 0 (radians)≤G12<2×π (radians).

Also, it is assumed that the phase changer 3801A performs phase changeon the symbols belonging to the second carrier group_2 in FIG. 74 byusing e^(j×G22) as the phase change value Vp(i). It is assumed that G22is a real number. For example, G22 is 0 (radians)≤G22<2×π (radians).

It is assumed that the phase changer 3801A performs phase change on thesymbols belonging to the third carrier group_2 in FIG. 74 by usinge^(j×G32) as the phase change value Vp(i). It is assumed that G32 is areal number. For example, G32 is 0 (radians)≤G32<2×π (radians).

It is assumed that the phase changer 3801A performs phase change on thesymbols belonging to the fourth carrier group_2 in FIG. 74 by usinge^(j×G42) as the phase change value Vp(i). It is assumed that G42 is areal number. For example, G42 is 0 (radians)≤G42 2×π (radians).

It is assumed that the phase changer 3801A performs phase change on thesymbols belonging to the fifth carrier group_2 in FIG. 74 by usinge^(j×G52) as the phase change value Vp(i). It is assumed that G52 is areal number. For example, G52 is 0 (radians)≤G52<2×π (radians).

As a first example, there is a method in which “G12≠G22 and G12≠G32 andG12≠G42 and G12≠G52 and G22≠G32 and G22≠G42 and G22≠G52 and G32≠G42 andG32≠G52 and G42≠G52” holds. When generalized, this is a method in which“x is an integer equal to or greater than 1, y is an integer equal to orgreater than 1, x≠y holds, and Gx2≠Gy2 holds in all x and all ysatisfying these conditions”.

As a second example, there is a method in which “G12≠G22 or G12≠G32 orG12≠G42 or G12≠G52 or G22≠G32 or G22≠G42 or G22≠G52 or G32≠G42 orG32≠G52 or G42≠G52” holds. When generalized, this is a method in which“there is a set of x and y in which x is an integer equal to or greaterthan 1, y is an integer equal to or greater than 1, x≠y holds, andGx2≠Gy2 holds”.

In addition, it is assumed that the phase changer 3801B performs phasechange on the symbols belonging to the first carrier group_2 in FIG. 74by using e^(j×H12) as the phase change value vp(i). It is assumed thatH12 is a real number. For example, H12 is 0 (radians)≤H12<2×π (radians).

Also, it is assumed that the phase changer 3801B performs phase changeon the symbols belonging to the second carrier group_2 in FIG. 74 byusing e^(j×H22) as the phase change value vp(i). It is assumed that H22is a real number. For example, H22 is 0 (radians)≤H22<2×π (radians).

It is assumed that the phase changer 3801B performs phase change on thesymbols belonging to the third carrier group_2 in FIG. 74 by usinge^(j×H32) as the phase change value vp(i). It is assumed that H32 is areal number. For example, H32 is 0 (radians)≤H32<2×π (radians).

It is assumed that the phase changer 3801B performs phase change on thesymbols belonging to the fourth carrier group_2 in FIG. 74 by usinge^(j×H42) as the phase change value vp(i). It is assumed that H42 is areal number. For example, H42 is 0 (radians)≤H42<2×π (radians).

It is assumed that the phase changer 3801B performs phase change on thesymbols belonging to the fifth carrier group_2 in FIG. 74 by usinge^(j×H52) as the phase change value vp(i). It is assumed that H52 is areal number. For example, H52 is 0 (radians)≤H52<2×π (radians).

As a first example, there is a method in which “H12≠H22 and H12≠H32 andH12≠H42 and H12≠H52 and H22≠H32 and H22≠H42 and H22≠H52 and H32≠H42 andH32≠H52 and H42≠H52” holds. When generalized, this is a method in which“x is an integer equal to or greater than 1, y is an integer equal to orgreater than 1, x≠y holds, and Hx2≠Hy2 holds in all x and all ysatisfying these conditions”.

As a second example, there is a method in which “H12≠H22 or H12≠H32 orH12≠H42 or H12≠H52 or H22≠H32 or H22≠H42 or H22≠H52 or H32≠H42 orH32≠H52 or H42≠H52” holds. When generalized, this is a method in which“there is a set of x and y in which x is an integer equal to or greaterthan 1, y is an integer equal to or greater than 1, x≠y holds, andHx2≠Hy2 holds”.

It is assumed that the phase changer 305A performs phase change on thesymbols belonging to the first carrier group_3 in FIG. 74 by usinge^(j×E13) as the phase change value Yp(i). It is assumed that E13 is areal number. For example, E13 is 0 (radians)≤E13<2×π (radians).

It is assumed that the phase changer 305A performs phase change on thesymbols belonging to the first carrier group_4 in FIG. 74 by usinge^(j×E14) as the phase change value Yp(i). It is assumed that E14 is areal number. For example, E14 is 0 (radians)≤E14<2×π (radians).

Also, it is assumed that the phase changer 305A performs phase change onthe symbols belonging to the second carrier group_4 in FIG. 74 by usinge^(j×E24) as the phase change value Yp(i). It is assumed that E24 is areal number. For example, E24 is 0 (radians)≤E24<2×π (radians).

It is assumed that the phase changer 305A performs phase change on thesymbols belonging to the third carrier group_4 in FIG. 74 by usinge^(j×E34) as the phase change value Yp(i). It is assumed that E34 is areal number. For example, E34 is 0 (radians)≤E34<2×π (radians).

As a first example, there is a method in which “E14≠E24 and E14≠E34 andE24≠E34” holds. When generalized, this is a method in which “x is aninteger equal to or greater than 1, y is an integer equal to or greaterthan 1, x≠y holds, and Ex4≠Ey4 holds in all x and all y satisfying theseconditions”.

As a second example, there is a method in which “E14≠E24 or E14≠E34 orE24≠E34” holds. When generalized, this is a method in which “there is aset of x and y in which x is an integer equal to or greater than 1, y isan integer equal to or greater than 1, x≠y holds, and Ex4≠Ey4 holds”.

In addition, it is assumed that the phase changer 305B performs phasechange on the symbols belonging to the first carrier group_4 in FIG. 74by using e^(j×F14) as the phase change value yp(i). It is assumed thatF14 is a real number. For example, F14 is 0 (radians)≤F14<2×π (radians).

Also, it is assumed that the phase changer 305B performs phase change onthe symbols belonging to the second carrier group_4 in FIG. 74 by usinge^(j×F24) as the phase change value yp(i). It is assumed that F24 is areal number. For example, F24 is 0 (radians)≤F24<2×π (radians).

It is assumed that the phase changer 305B performs phase change on thesymbols belonging to the third carrier group_4 in FIG. 74 by usinge^(j×F34) as the phase change value yp(i). It is assumed that F34 is areal number. For example, F34 is 0 (radians)≤F34<2×π (radians).

As a first example, there is a method in which “F14≠F24 and F14≠F34 andF24≠F34” holds. When generalized, this is a method in which “x is aninteger equal to or greater than 1, y is an integer equal to or greaterthan 1, x≠y holds, and Fx4≠Fy4 holds in all x and all y satisfying theseconditions”.

As a second example, there is a method in which “F14≠F24 or F14≠F34 orF24≠F34” holds. When generalized, this is a method in which “there is aset of x and y in which x is an integer equal to or greater than 1, y isan integer equal to or greater than 1, x≠y holds, and Fx4≠Fy4 holds”.

In addition, it is assumed that the phase changer 3801A performs phasechange on the symbols belonging to the first carrier group_4 in FIG. 74by using e^(j×G14) as the phase change value Vp(i). It is assumed thatG14 is a real number. For example, G14 is 0 (radians)≤G14<2×π (radians).

Also, it is assumed that the phase changer 3801A performs phase changeon the symbols belonging to the second carrier group_4 in FIG. 74 byusing e^(j×G24) as the phase change value Vp(i). It is assumed that G24is a real number. For example, G24 is 0 (radians)≤G24<2×π (radians).

It is assumed that the phase changer 3801A performs phase change on thesymbols belonging to the third carrier group_4 in FIG. 74 by usinge^(j×G34) as the phase change value Vp(i). It is assumed that G34 is areal number. For example, G34 is 0 (radians)≤G34<2×π (radians).

For example, as a first example, there is a method in which “G14≠G24 andG14≠G34 and G24≠G34” holds. When generalized, this is a method in which“x is an integer equal to or greater than 1, y is an integer equal to orgreater than 1, x≠y holds, and Gx4≠Gy4 holds in all x and all ysatisfying these conditions”.

As a second example, there is a method in which “G14≠G24 or G14≠G34 orG24≠G34” holds. When generalized, this is a method in which “there is aset of x and y in which x is an integer equal to or greater than 1, y isan integer equal to or greater than 1, x≠y holds, and Gx4≠Gy4 holds”.

In addition, it is assumed that the phase changer 3801B performs phasechange on the symbols belonging to the first carrier group_4 in FIG. 74by using e^(j×H14) as the phase change value vp(i). It is assumed thatH14 is a real number. For example, H14 is 0 (radians)≤H14<2×π (radians).

Also, it is assumed that the phase changer 3801B performs phase changeon the symbols belonging to the second carrier group_4 in FIG. 74 byusing e^(j×H24) as the phase change value vp(i). It is assumed that H24is a real number. For example, H24 is 0 (radians)≤H24<2×π (radians).

It is assumed that the phase changer 3801B performs phase change on thesymbols belonging to the third carrier group_4 in FIG. 74 by usinge^(j×H34) as the phase change value vp(i). It is assumed that H34 is areal number. For example, H34 is 0 (radians)≤H34<2×π (radians).

As a first example, there is a method in which “H14≠H24 and H14≠H34 andH24≠H34” holds. When generalized, this is a method in which “x is aninteger equal to or greater than 1, y is an integer equal to or greaterthan 1, x≠y holds, and Hx4≠Hy4 holds in all x and all y satisfying theseconditions”.

As a second example, there is a method in which “H14≠H24 or H14≠H34 orH24≠H34” holds. When generalized, this is a method in which “there is aset of x and y in which x is an integer equal to or greater than 1, y isan integer equal to or greater than 1, x≠y holds, and Hx4≠Hy4 holds”.

At this time, the following characteristic may be included.

When the method for dividing frequencies is the same, like “the sectionfrom time $1 to time $3” and “from time $4 to time $9” (the frequencyused by the first carrier group_1 and the frequency used by the firstcarrier group_2 are identical to each other, or the frequency used bythe second carrier group_1 and the frequency used by the second carriergroup_2 are identical to each other, or the frequency used by the thirdcarrier group_1 and the frequency used by the third carrier group_2 areidentical to each other, or the frequency used by the fourth carriergroup_1 and the frequency used by the fourth carrier group_2 areidentical to each other, or the frequency used by the fifth carriergroup_1 and the frequency used by the fifth carrier group_2 areidentical to each other), the phase change value used by the X-thcarrier group_1 (X is 1, 2, 3, 4, or 5) in “the section from time $1 totime $3” and the phase change value used by the X-th carrier group_2 in“the section from time $4 to time $9” may be identical to or differentfrom each other.

For example, E11=E12 may hold, or E11≠E12 may hold. E21=E22 may hold, orE21≠E22 may hold. E31=E32 may hold, or E31≠E32 may hold. E41=E42 mayhold, or E41≠E42 may hold. E51=E52 may hold, or E51≠E52 may hold.

Also, F11=F12 may hold, or F11≠F12 may hold. F21=F22 may hold, orF21≠F22 may hold. F31=F32 may hold, or F31≠F32 may hold. F41=F42 mayhold, or F41≠F42 may hold. F51=F52 may hold, or F51≠F52 may hold.

G11=G12 may hold, or G11≠G12 may hold. G21=G22 may hold, or G21≠G22 mayhold. G31=G32 may hold, or G31≠G32 may hold. G41=G42 may hold, orG41≠G42 may hold. G51=G52 may hold, or G51≠G52 may hold.

H11=H12 may hold, or H11≠H12 may hold. H21=H22 may hold, or H21≠H22 mayhold. H31=H32 may hold, or H31≠H32 may hold. H41=H42 may hold, orH41≠H42 may hold. H51=H52 may hold, or H51≠H52 may hold.

The method for dividing frequencies may be changed along the time axis.For example, “from time $1 to time $3” in FIG. 74 , carrier #1 tocarrier #25 are divided into five groups to generate five carriergroups. Also, “from time $10 to time $11”, one carrier group made up ofcarrier #1 to carrier #25 is generated. In addition, “from time $12 totime $14”, carrier #1 to carrier #25 are divided into three groups togenerate three carrier groups.

The method for dividing frequencies is not limited to the method in FIG.74 . The frequencies allocated to a certain user may serve as onecarrier group, or two or more carrier groups may be generated. Inaddition, it is sufficient that the number of carriers constituting acarrier group be one or more.

According to the description given above using FIG. 74 , “carrier #1 tocarrier #25 and time $1 to time $14 are used by the base station or APto transmit data to a certain terminal (certain user) (terminal #p)”.Alternatively, carrier #1 to carrier #25 and time $1 to time $14 may beallocated for transmitting data to multiple terminals (multiple users)by the base station or AP. Hereinafter, this point will be described.The settings for each carrier group of the phase change value Yp(i) usedby the phase changer 305A, the phase change value yp(i) used by thephase changer 305B, the phase change value Vp(i) used by the phasechanger 3801A, and the phase change value vp(i) used by the phasechanger 3801B in FIGS. 3, 4, 26, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47,48, 52 , and so forth are as described above, and thus the descriptionthereof is omitted.

As a first example, in FIG. 74 , terminal allocation (user allocation)may be performed by using time division.

For example, it is assumed that the base station or AP transmits data toa terminal (user) p1 (i.e., p=p1) by using “time $1 to time #3”. Also,it is assumed that the base station or AP transmits data to a terminal(user) p2 (i.e., p=p2) by using “time $4 to time #9”. It is assumed thatthe base station or AP transmits data to a terminal (user) p3 (i.e.,p=p3) by using “time $10 to time $11”. It is assumed that the basestation or AP transmits data to a terminal (user) p4 (i.e., p=p4) byusing “time $12 to time $14”.

As a second example, in FIG. 74 , terminal allocation (user allocation)may be performed by using frequency division.

For example, it is assumed that the base station or AP transmits data tothe terminal (user) p1 (i.e., p=p1) by using the first carrier group_1and the second carrier group_1. Also, it is assumed that the basestation or AP transmits data to the terminal (user) p2 (i.e., p=p2) byusing the third carrier group_1, the fourth carrier group_1, and thefifth carrier group_1.

As a third example, in FIG. 74 , terminal allocation (user allocation)may be performed by using both time division and frequency division.

For example, it is assumed that the base station or AP transmits data tothe terminal (user) p1 (i.e., p=p1) by using the first carrier group_1,the first carrier group_2, the second carrier group_1, and the secondcarrier group_2. Also, it is assumed that the base station or APtransmits data to the terminal (user) p2 (i.e., p=p2) by using the thirdcarrier group_1, the fourth carrier group_1, and the fifth carriergroup_1. It is assumed that the base station or AP transmits data to theterminal (user) p3 (i.e., p=p3) by using the third carrier group_2 andthe fourth carrier group_2. It is assumed that the base station or APtransmits data to the terminal (user) p4 (i.e., p=p4) by using the fifthcarrier group_2. It is assumed that the base station or AP transmitsdata to a terminal (user) p5 (i.e., p=p5) by using the first carriergroup_3. It is assumed that the base station or AP transmits data to aterminal (user) p6 (i.e., p=p6) by using the first carrier group_4. Itis assumed that the base station or AP transmits data to a terminal(user) p7 (i.e., p=p7) by using the second carrier group_4 and the thirdcarrier group_4.

In the description given above, the method for configuring carriergroups is not limited to FIG. 74 . For example, the number of carriersconstituting a carrier group is not specified as long as the number isone or more. In addition, the time interval for configuring carriergroups is not limited to the configuration in FIG. 74 . In addition, thefrequency division method, the time division method, and the time andfrequency division method for user allocation are not limited to theexamples described above, and any type of division may be used to carryout the embodiment.

In accordance with the above examples, by “changing the phaseperiodically or regularly” in the phase changer 305B, the phase changer305A, the phase changer 309A, the phase changer 3801B, and the phasechanger 3801A in FIGS. 3, 4, 26, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47,48, 52 , and so forth described in the first to fifteenth embodiments,the first to fourth supplements, and so forth, the effects described inthe first to fifteenth embodiments, the first to fourth supplements, andso forth can be obtained.

In FIGS. 3, 4, 26, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48 , and soforth, the portion located downstream of the inserter 307A and theinserter 307B may have the configuration in FIG. 75 . FIG. 75 is adiagram illustrating an example of a configuration added with a phasechanger. The characteristic point of FIG. 75 is that the phase changer309A is inserted. The operation of the phase changer 309A is, like thatof the phase changer 309B, signal processing for phase change or CDD(CSD).

Seventeenth Embodiment

In the first to fifteenth embodiments, the first to fourth supplements,and so forth, when both “the phase changer 305B, the phase changer 305A,the phase changer 309A, the phase changer 3801B, and the phase changer3801A in FIGS. 3, 4, 26, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 52, and so forth” and the computation in the weight combiner 303 areconsidered together, for example, this corresponds to switching of theprecoding matrix by i when consideration is given with reference toExpression (37), Expression (42), Expression (49), Expression (51),Expression (64), and Expression (65), for example.

In addition, in a case where Expression (21), Expression (22),Expression (23), Expression (24), Expression (25), Expression (26),Expression (27), and Expression (28) are used in the weight combiner303, for example, this corresponds to switching of the precoding matrixby i.

When consideration is given with reference to Expression (37),Expression (42), Expression (49), Expression (51), Expression (64), andExpression (65), when the precoding matrix is switched by i, Expression(69) holds. Here, i is a symbol number, and i is an integer equal to orgreater than 0, for example.

$\begin{matrix}\begin{matrix}{\begin{pmatrix}{{zp}1(i)} \\{{zp}2(i)}\end{pmatrix} = {{{Fp}(i)}\begin{pmatrix}{{sp}1(i)} \\{{sp}2(i)}\end{pmatrix}}} \\{= {\begin{pmatrix}{{ap}(i)} & {{bp}(i)} \\{{cp}(i)} & {{dp}(i)}\end{pmatrix}\begin{pmatrix}{{sp}1(i)} \\{{sp}2(i)}\end{pmatrix}}}\end{matrix} & {{Expression}(69)}\end{matrix}$

In Expression (69), zp1(i) represents a first phase-changed signal,zp2(i) represents a second phase-changer signal, sp1(i) represents theuser #p mapped signal 301A, and sp2(i) represents the user #p mappedsignal 301B. Fp(i) represents a matrix used for weight combining, thatis, a precoding matrix. The precoding matrix can be regarded as afunction of i. For example, the precoding matrix may be switchedperiodically or regularly. Note that, in the present embodiment, zp1(i)is called a first precoded signal, and zp2(i) is called a secondprecoded signal. On the basis of Expression (69), Expression (70) holds.

$\begin{matrix}{{{Fp}(i)} = \begin{pmatrix}{{ap}(i)} & {{bp}(i)} \\{{cp}(i)} & {{dp}(i)}\end{pmatrix}} & {{Expression}(70)}\end{matrix}$

In Expression (70), ap(i) can be defined as a complex number. Thus,ap(i) may be a real number. In addition, bp(i) can be defined as acomplex number. Thus, bp(i) may be a real number. In addition, cp(i) canbe defined as a complex number. Thus, cp(i) may be a real number. Inaddition, dp(i) can be defined as a complex number. Thus, dp(i) may be areal number.

Similarly to the description of Expression (37), Expression (42),Expression (49), Expression (51), Expression (64), and Expression (65),zp1(i) corresponds to 103_p_1 in FIG. 1 , and zp2(i) corresponds to103_p_2 in FIG. 1 . Alternatively, zp1(i) corresponds to 103_p_1 in FIG.70 , and zp2(i) corresponds to 103_p_2 in FIG. 70 . Here, zp1(i) zp2(i)are transmitted by using identical frequencies and identical times.

FIG. 76 is a diagram illustrating a first example configuration of theuser #p signal processor 102_p in FIGS. 1 and 70 including the abovecomputation (Expression (69)). In FIG. 76 , the elements that operatesimilarly to those in FIG. 3 and so forth are denoted by the samenumerals, and the detailed description thereof is omitted.

The computation of Expression (69) is performed by a weight combinerA401 in FIG. 76 .

FIG. 77 is a diagram illustrating a second example configuration of theuser #p signal processor 102_p in FIGS. 1 and 70 including the abovecomputation (Expression (69)). In FIG. 77 , the elements that operatesimilarly to those in FIG. 3 and so forth are denoted by the samenumerals, and the detailed description thereof is omitted.

As in FIG. 76 , the computation of Expression (69) is performed by theweight combiner A401 in FIG. 77 . The characteristic point is that theweight combiner A401 performs precoding processing by switching theprecoding matrix regularly or periodically, for example. In FIG. 77 ,the point different from FIG. 76 is that the phase changer 309A isinserted. The details of the operation of switching of precoding will bedescribed below. The operation of the phase changer 309A is, like thatof the phase changer 309B, signal processing for phase change or CDD(CSD).

Although not illustrated in FIGS. 76 and 77 , the pilot symbol signal(pa(t)) (351A), the pilot symbol signal (pb(t)) (351B), the preamblesignal 352, and the control information symbol signal 353 may be signalsthat have been subjected to processing such as phase change.

Also, zp1(i) and zp2(i) are subjected to the processing illustrated inFIG. 1 or 70 . This point is as described in the foregoing embodiments.

Meanwhile, in the first to fifteenth embodiments, the first to fourthsupplements, and so forth, a description is given, using, for example,Expression (2), Expression (50), and so forth, of the phase changer305B, the phase changer 305A, the phase changer 309A, the phase changer3801B, and the phase changer 3801A in FIGS. 3, 4, 26, 38, 39, 40, 41,42, 43, 44, 45, 46, 47, 48, 52 , and so forth, and also a description isgiven that the value of the phase change value need not be based onthese expressions and “it is sufficient to change the phase periodicallyor regularly”. Thus, the precoding matrix expressed by Expression (70)in Expression (69) “may be changed periodically or regularly”.Hereinafter, a description will be given of an example of changing theprecoding matrix periodically or regularly.

For example, as in FIG. 73 , the first carrier group made up of carrier#1 to carrier #5, the second carrier group made up of carrier #6 tocarrier #10, the third carrier group made up of carrier #11 to carrier#15, the fourth carrier group made up of carrier #16 to carrier #20, andthe fifth carrier group made up of carrier #21 to carrier #25 areconsidered, and it is assumed that the base station or AP uses the firstcarrier group, the second carrier group, the third carrier group, thefourth carrier group, and the fifth carrier group to transmit data to acertain terminal (certain user) (terminal #p).

At this time, it is assumed that precoding is performed on the symbol(set) (sp1(i) and sp2(i)) belonging to the first carrier group in FIG.73 by using U1 as the precoding matrix Fp(i) in Expression (69) andExpression (70).

Also, it is assumed that precoding is performed on the symbol (set)(sp1(i) and sp2(i)) belonging to the second carrier group in FIG. 73 byusing U2 as the precoding matrix Fp(i) in Expression (69) and Expression(70).

It is assumed that precoding is performed on the symbol (set) (sp1(i)and sp2(i)) belonging to the third carrier group in FIG. 73 by using U3as the precoding matrix Fp(i) in Expression (69) and Expression (70).

It is assumed that precoding is performed on the symbol (set) (sp1(i)and sp2(i)) belonging to the fourth carrier group in FIG. 73 by using U4as the precoding matrix Fp(i) in Expression (69) and Expression (70).

It is assumed that precoding is performed on the symbol (set) (sp1(i)and sp2(i)) belonging to the fifth carrier group in FIG. 73 by using U5as the precoding matrix Fp(i) in Expression (69) and Expression (70).

As a first example, there is a method in which “U1≠U2 and U1≠U3 andU1≠U4 and U1≠U5 and U2≠U3 and U2≠U4 and U2≠U5 and U3≠U4 and U3≠U5 andU4≠U5” holds. When generalized, this is a method in which “x is aninteger equal to or greater than 1, y is an integer equal to or greaterthan 1, x≠y holds, and Ux≠Uy holds in all x and all y satisfying theseconditions”.

As a second example, there is a method in which “U1≠U2 or U1≠U3 or U1≠U4or U1≠U5 or U2≠U3 or U2≠U4 or U2≠U5 or U3≠U4 or U3≠U5 or U4≠U5” holds.When generalized, this is a method in which “there is a set of x and yin which x is an integer equal to or greater than 1, y is an integerequal to or greater than 1, x≠y holds, and Ux≠Uy holds”.

FIG. 73 illustrates the first carrier group to the fifth carrier group,but the number of carrier groups is not limited to five. The embodimentcan be carried out similarly when two or more carrier groups exist.Alternatively, the number of carrier groups may be set to one. Forexample, one or more carrier groups may exist on the basis of acommunication situation, feedback information from a terminal, or thelike. When there is one carrier group, the precoding matrix is notchanged. As in the example in FIG. 73 , each carrier group may be set toa value of a fixed number.

In addition, each of the first carrier group, the second carrier group,the third carrier group, the fourth carrier group, and the fifth carriergroup has a configuration including five carriers, but the configurationis not limited thereto. Thus, it is sufficient for each carrier group toinclude one or more carriers. Among different carrier groups, the numberof carriers included may be identical or different. For example, in FIG.73 , the number of carriers included in the first carrier group is five,and the number of carriers included in the second carrier group is alsofive (identical). For another example, in FIG. 73 , the number ofcarriers included in the first carrier group may be five, and the numberof carriers included in the second carrier group may be different, forexample, ten.

The matrices U1, U2, U3, U4, and U5 may be expressed by, for example,the matrix on the left side of Expression (5), the matrix on the leftside of Expression (6), the matrix on the left side of Expression (7),the matrix on the left side of Expression (8), the matrix on the leftside of Expression (9), the matrix on the left side of Expression (10),the matrix on the left side of Expression (11), the matrix on the leftside of Expression (12), the matrix on the left side of Expression (13),the matrix on the left side of Expression (14), the matrix on the leftside of Expression (15), the matrix on the left side of Expression (16),the matrix on the left side of Expression (17), the matrix on the leftside of Expression (18), the matrix on the left side of Expression (19),the matrix on the left side of Expression (20), the matrix on the leftside of Expression (21), the matrix on the left side of Expression (22),the matrix on the left side of Expression (23), the matrix on the leftside of Expression (24), the matrix on the left side of Expression (25),the matrix on the left side of Expression (26), the matrix on the leftside of Expression (27), the matrix on the left side of Expression (28),the matrix on the left side of Expression (29), the matrix on the leftside of Expression (30), the matrix on the left side of Expression (31),the matrix on the left side of Expression (32), the matrix on the leftside of Expression (33), the matrix on the left side of Expression (34),the matrix on the left side of Expression (35), the matrix on the leftside of Expression (36), and so forth, but the matrices are not limitedthereto.

That is, the precoding matrix Fp(i) may be any kind of matrix, such asthe matrix on the left side of Expression (5), the matrix on the leftside of Expression (6), the matrix on the left side of Expression (7),the matrix on the left side of Expression (8), the matrix on the leftside of Expression (9), the matrix on the left side of Expression (10),the matrix on the left side of Expression (11), the matrix on the leftside of Expression (12), the matrix on the left side of Expression (13),the matrix on the left side of Expression (14), the matrix on the leftside of Expression (15), the matrix on the left side of Expression (16),the matrix on the left side of Expression (17), the matrix on the leftside of Expression (18), the matrix on the left side of Expression (19),the matrix on the left side of Expression (20), the matrix on the leftside of Expression (21), the matrix on the left side of Expression (22),the matrix on the left side of Expression (23), the matrix on the leftside of Expression (24), the matrix on the left side of Expression (25),the matrix on the left side of Expression (26), the matrix on the leftside of Expression (27), the matrix on the left side of Expression (28),the matrix on the left side of Expression (29), the matrix on the leftside of Expression (30), the matrix on the left side of Expression (31),the matrix on the left side of Expression (32), the matrix on the leftside of Expression (33), the matrix on the left side of Expression (34),the matrix on the left side of Expression (35), and the matrix on theleft side of Expression (36).

FIG. 74 illustrates an example of carrier groups of modulated signalstransmitted by the base station or AP different from the example in FIG.73 , in which the horizontal axis indicates frequency (carrier) and thevertical axis indicates time.

The first carrier group_1 is made up of carrier #1 to carrier #5 andtime $1 to time $3. The second carrier group_1 is made up of carrier #6to carrier #10 and time $1 to time $3. The third carrier group_1 is madeup of carrier #11 to carrier #15 and time $1 to time $3. The fourthcarrier group_1 is made up of carrier #16 to carrier #20 and time $1 totime $3. The fifth carrier group_1 is made up of carrier #21 to carrier#25 and time $1 to time $3.

The first carrier group_2 is made up of carrier #1 to carrier #5 andtime $4 to time $9. The second carrier group_2 is made up of carrier #6to carrier #10 and time $4 to time $9. The third carrier group_2 is madeup of carrier #11 to carrier #15 and time $4 to time $9. The fourthcarrier group_2 is made up of carrier #16 to carrier #20 and time $4 totime $9. The fifth carrier group_2 is made up of carrier #21 to carrier#25 and time $4 to time $9.

The first carrier group_3 is made up of carrier #1 to carrier #25 andtime $10 to time $11.

The first carrier group_4 is made up of carrier #1 to carrier #10 andtime $12 to time $14. The second carrier group_4 is made up of carrier#11 to carrier #15 and time $12 to time $14. The third carrier group_4is made up of carrier #16 to carrier #25 and time $12 to time $14.

In FIG. 74 , it is assumed that the base station or AP uses carrier #1to carrier #25 and time $1 to time $14 to transmit data to a certainterminal (certain user) (terminal #p).

At this time, it is assumed that precoding is performed on the symbol(set) (sp1(i) and sp2(i)) belonging to the first carrier group_1 in FIG.74 by using a matrix U11 as the precoding matrix Fp(i) in Expression(69) and Expression (70).

Also, it is assumed that precoding is performed on the symbol (set)(sp1(i) and sp2(i)) belonging to the second carrier group_1 in FIG. 74by using a matrix U21 as the precoding matrix Fp(i) in Expression (69)and Expression (70).

It is assumed that precoding is performed on the symbol (set) (sp1(i)and sp2(i)) belonging to the third carrier group_1 in FIG. 74 by using amatrix U31 as the precoding matrix Fp(i) in Expression (69) andExpression (70).

It is assumed that precoding is performed on the symbol (set) (sp1(i)and sp2(i)) belonging to the fourth carrier group_1 in FIG. 74 by usinga matrix U41 as the precoding matrix Fp(i) in Expression (69) andExpression (70).

It is assumed that precoding is performed on the symbol (set) (sp1(i)and sp2(i)) belonging to the fifth carrier group_1 in FIG. 74 by using amatrix U51 as the precoding matrix Fp(i) in Expression (69) andExpression (70).

As a first example, there is a method in which “U11≠U21 and U11≠U31 andU11≠U41 and U11≠U51 and U21≠U31 and U21≠U41 and U21≠U51 and U31≠U41 andU31≠U51 and U41≠U51” holds. When generalized, this is a method in which“x is an integer equal to or greater than 1, y is an integer equal to orgreater than 1, x≠y holds, and Ux1≠Uy1 holds in all x and all ysatisfying these conditions”.

As a second example, there is a method in which “U11≠U21 or U11≠U31 orU11≠U41 or U11≠U51 or U21≠U31 or U21≠U41 or U21≠U51 or U31≠U41 orU31≠U51 or U41≠U51” holds. When generalized, this is a method in which“there is a set of x and y in which x is an integer equal to or greaterthan 1, y is an integer equal to or greater than 1, x≠y holds, andUx1≠Uy1 holds”.

The matrices U11, U21, U31, U41, and U51 may be expressed by, forexample, the matrix on the left side of Expression (5), the matrix onthe left side of Expression (6), the matrix on the left side ofExpression (7), the matrix on the left side of Expression (8), thematrix on the left side of Expression (9), the matrix on the left sideof Expression (10), the matrix on the left side of Expression (11), thematrix on the left side of Expression (12), the matrix on the left sideof Expression (13), the matrix on the left side of Expression (14), thematrix on the left side of Expression (15), the matrix on the left sideof Expression (16), the matrix on the left side of Expression (17), thematrix on the left side of Expression (18), the matrix on the left sideof Expression (19), the matrix on the left side of Expression (20), thematrix on the left side of Expression (21), the matrix on the left sideof Expression (22), the matrix on the left side of Expression (23), thematrix on the left side of Expression (24), the matrix on the left sideof Expression (25), the matrix on the left side of Expression (26), thematrix on the left side of Expression (27), the matrix on the left sideof Expression (28), the matrix on the left side of Expression (29), thematrix on the left side of Expression (30), the matrix on the left sideof Expression (31), the matrix on the left side of Expression (32), thematrix on the left side of Expression (33), the matrix on the left sideof Expression (34), the matrix on the left side of Expression (35), thematrix on the left side of Expression (36), and so forth, but thematrices are not limited thereto.

That is, the precoding matrix Fp(i) may be any kind of matrix, such asthe matrix on the left side of Expression (5), the matrix on the leftside of Expression (6), the matrix on the left side of Expression (7),the matrix on the left side of Expression (8), the matrix on the leftside of Expression (9), the matrix on the left side of Expression (10),the matrix on the left side of Expression (11), the matrix on the leftside of Expression (12), the matrix on the left side of Expression (13),the matrix on the left side of Expression (14), the matrix on the leftside of Expression (15), the matrix on the left side of Expression (16),the matrix on the left side of Expression (17), the matrix on the leftside of Expression (18), the matrix on the left side of Expression (19),the matrix on the left side of Expression (20), the matrix on the leftside of Expression (21), the matrix on the left side of Expression (22),the matrix on the left side of Expression (23), the matrix on the leftside of Expression (24), the matrix on the left side of Expression (25),the matrix on the left side of Expression (26), the matrix on the leftside of Expression (27), the matrix on the left side of Expression (28),the matrix on the left side of Expression (29), the matrix on the leftside of Expression (30), the matrix on the left side of Expression (31),the matrix on the left side of Expression (32), the matrix on the leftside of Expression (33), the matrix on the left side of Expression (34),the matrix on the left side of Expression (35), and the matrix on theleft side of Expression (36).

In addition, it is assumed that precoding is performed on the symbol(set) (sp1(i) and sp2(i)) belonging to the first carrier group_2 in FIG.74 by using a matrix U12 as the precoding matrix Fp(i) in Expression(69) and Expression (70).

Also, it is assumed that precoding is performed on the symbol (set)(sp1(i) and sp2(i)) belonging to the second carrier group_2 in FIG. 74by using a matrix U22 as the precoding matrix Fp(i) in Expression (69)and Expression (70).

It is assumed that precoding is performed on the symbol (set) (sp1(i)and sp2(i)) belonging to the third carrier group_2 in FIG. 74 by using amatrix U32 as the precoding matrix Fp(i) in Expression (69) andExpression (70).

It is assumed that precoding is performed on the symbol (set) (sp1(i)and sp2(i)) belonging to the fourth carrier group_2 in FIG. 74 by usinga matrix U42 as the precoding matrix Fp(i) in Expression (69) andExpression (70).

It is assumed that precoding is performed on the symbol (set) (sp1(i)and sp2(i)) belonging to the fifth carrier group_2 in FIG. 74 by using amatrix U52 as the precoding matrix Fp(i) in Expression (69) andExpression (70).

As a first example, there is a method in which “U12≠U22 and U12≠U32 andU12≠U42 and U12≠U52 and U22≠U32 and U22≠U42 and U22≠U52 and U32≠U42 andU32≠U52 and U42≠U52” holds. When generalized, this is a method in which“x is an integer equal to or greater than 1, y is an integer equal to orgreater than 1, x≠y holds, and Ux2≠Uy2 holds in all x and all ysatisfying these conditions”.

As a second example, there is a method in which “U12≠U22 or U12≠U32 orU12≠U42 or U12≠U52 or U22≠U32 or U22≠U42 or U22≠U52 or U32≠U42 orU32≠U52 or U42≠U52” holds. When generalized, this is a method in which“there is a set of x and y in which x is an integer equal to or greaterthan 1, y is an integer equal to or greater than 1, x≠y holds, andUx2≠Uy2 holds”.

The matrices U12, U22, U32, U42, and U52 may be expressed by, forexample, the matrix on the left side of Expression (5), the matrix onthe left side of Expression (6), the matrix on the left side ofExpression (7), the matrix on the left side of Expression (8), thematrix on the left side of Expression (9), the matrix on the left sideof Expression (10), the matrix on the left side of Expression (11), thematrix on the left side of Expression (12), the matrix on the left sideof Expression (13), the matrix on the left side of Expression (14), thematrix on the left side of Expression (15), the matrix on the left sideof Expression (16), the matrix on the left side of Expression (17), thematrix on the left side of Expression (18), the matrix on the left sideof Expression (19), the matrix on the left side of Expression (20), thematrix on the left side of Expression (21), the matrix on the left sideof Expression (22), the matrix on the left side of Expression (23), thematrix on the left side of Expression (24), the matrix on the left sideof Expression (25), the matrix on the left side of Expression (26), thematrix on the left side of Expression (27), the matrix on the left sideof Expression (28), the matrix on the left side of Expression (29), thematrix on the left side of Expression (30), the matrix on the left sideof Expression (31), the matrix on the left side of Expression (32), thematrix on the left side of Expression (33), the matrix on the left sideof Expression (34), the matrix on the left side of Expression (35), thematrix on the left side of Expression (36), and so forth, but thematrices are not limited thereto.

That is, the precoding matrix Fp(i) may be any kind of matrix, such asthe matrix on the left side of Expression (5), the matrix on the leftside of Expression (6), the matrix on the left side of Expression (7),the matrix on the left side of Expression (8), the matrix on the leftside of Expression (9), the matrix on the left side of Expression (10),the matrix on the left side of Expression (11), the matrix on the leftside of Expression (12), the matrix on the left side of Expression (13),the matrix on the left side of Expression (14), the matrix on the leftside of Expression (15), the matrix on the left side of Expression (16),the matrix on the left side of Expression (17), the matrix on the leftside of Expression (18), the matrix on the left side of Expression (19),the matrix on the left side of Expression (20), the matrix on the leftside of Expression (21), the matrix on the left side of Expression (22),the matrix on the left side of Expression (23), the matrix on the leftside of Expression (24), the matrix on the left side of Expression (25),the matrix on the left side of Expression (26), the matrix on the leftside of Expression (27), the matrix on the left side of Expression (28),the matrix on the left side of Expression (29), the matrix on the leftside of Expression (30), the matrix on the left side of Expression (31),the matrix on the left side of Expression (32), the matrix on the leftside of Expression (33), the matrix on the left side of Expression (34),the matrix on the left side of Expression (35), and the matrix on theleft side of Expression (36).

It is assumed that precoding is performed on the symbol (set) (sp1(i)and sp2(i)) belonging to the first carrier group_3 in FIG. 74 by using amatrix U13 as the precoding matrix Fp(i) in Expression (69) andExpression (70).

It is assumed that precoding is performed on the symbol (set) (sp1(i)and sp2(i)) belonging to the first carrier group_4 in FIG. 74 by using amatrix U14 as the precoding matrix Fp(i) in Expression (69) andExpression (70).

It is assumed that precoding is performed on the symbol (set) (sp1(i)and sp2(i)) belonging to the second carrier group_4 in FIG. 74 by usinga matrix U24 as the precoding matrix Fp(i) in Expression (69) andExpression (70).

It is assumed that precoding is performed on the symbol (set) (sp1(i)and sp2(i)) belonging to the third carrier group_4 in FIG. 74 by using amatrix U34 as the precoding matrix Fp(i) in Expression (69) andExpression (70).

As a first example, there is a method in which “U14≠U24 and U14≠U34 andU24≠U34” holds. When generalized, this is a method in which “x is aninteger equal to or greater than 1, y is an integer equal to or greaterthan 1, x≠y holds, and Ux4≠Uy4 holds in all x and all y satisfying theseconditions”.

As a second example, there is a method in which “U14≠U24 or U14≠U34 orU24≠U34” holds. When generalized, this is a method in which “there is aset of x and y in which x is an integer equal to or greater than 1, y isan integer equal to or greater than 1, x≠y holds, and Ux4≠Uy4 holds”.

The matrices U14, U24, and U34 may be expressed by, for example, thematrix on the left side of Expression (5), the matrix on the left sideof Expression (6), the matrix on the left side of Expression (7), thematrix on the left side of Expression (8), the matrix on the left sideof Expression (9), the matrix on the left side of Expression (10), thematrix on the left side of Expression (11), the matrix on the left sideof Expression (12), the matrix on the left side of Expression (13), thematrix on the left side of Expression (14), the matrix on the left sideof Expression (15), the matrix on the left side of Expression (16), thematrix on the left side of Expression (17), the matrix on the left sideof Expression (18), the matrix on the left side of Expression (19), thematrix on the left side of Expression (20), the matrix on the left sideof Expression (21), the matrix on the left side of Expression (22), thematrix on the left side of Expression (23), the matrix on the left sideof Expression (24), the matrix on the left side of Expression (25), thematrix on the left side of Expression (26), the matrix on the left sideof Expression (27), the matrix on the left side of Expression (28), thematrix on the left side of Expression (29), the matrix on the left sideof Expression (30), the matrix on the left side of Expression (31), thematrix on the left side of Expression (32), the matrix on the left sideof Expression (33), the matrix on the left side of Expression (34), thematrix on the left side of Expression (35), the matrix on the left sideof Expression (36), and so forth, but the matrices are not limitedthereto.

That is, the precoding matrix Fp(i) may be any kind of matrix, such asthe matrix on the left side of Expression (5), the matrix on the leftside of Expression (6), the matrix on the left side of Expression (7),the matrix on the left side of Expression (8), the matrix on the leftside of Expression (9), the matrix on the left side of Expression (10),the matrix on the left side of Expression (11), the matrix on the leftside of Expression (12), the matrix on the left side of Expression (13),the matrix on the left side of Expression (14), the matrix on the leftside of Expression (15), the matrix on the left side of Expression (16),the matrix on the left side of Expression (17), the matrix on the leftside of Expression (18), the matrix on the left side of Expression (19),the matrix on the left side of Expression (20), the matrix on the leftside of Expression (21), the matrix on the left side of Expression (22),the matrix on the left side of Expression (23), the matrix on the leftside of Expression (24), the matrix on the left side of Expression (25),the matrix on the left side of Expression (26), the matrix on the leftside of Expression (27), the matrix on the left side of Expression (28),the matrix on the left side of Expression (29), the matrix on the leftside of Expression (30), the matrix on the left side of Expression (31),the matrix on the left side of Expression (32), the matrix on the leftside of Expression (33), the matrix on the left side of Expression (34),the matrix on the left side of Expression (35), and the matrix on theleft side of Expression (36).

At this time, the following characteristic may be included.

When the method for dividing frequencies is the same, like “the sectionfrom time $1 to time $3” and “from time $4 to time $9” (the frequencyused by the first carrier group_1 and the frequency used by the firstcarrier group_2 are identical to each other, or the frequency used bythe second carrier group_1 and the frequency used by the second carriergroup_2 are identical to each other, or the frequency used by the thirdcarrier group_1 and the frequency used by the third carrier group_2 areidentical to each other, or the frequency used by the fourth carriergroup_1 and the frequency used by the fourth carrier group_2 areidentical to each other, or the frequency used by the fifth carriergroup_1 and the frequency used by the fifth carrier group_2 areidentical to each other), the precoding matrix used by the X-th carriergroup_1 (X is 1, 2, 3, 4, or 5) in “the section from time $1 to time $3”and the precoding matrix used by the X-th carrier group_2 in “thesection from time $4 to time $9” may be identical to or different fromeach other.

For example, U11=U12 may hold, or U11≠U12 may hold. U21=U22 may hold, orU21≠U22 may hold. U31=U32 may hold, or U31≠U32 may hold. U41=U42 mayhold, or U41≠U42 may hold. U51=U52 may hold, or U51≠U52 may hold.

The method for dividing frequencies may be changed along the time axis.For example, “from time $1 to time $3” in FIG. 74 , carrier #1 tocarrier #25 are divided into five groups to generate five carriergroups. Also, “from time $10 to time $11”, one carrier group made up ofcarrier #1 to carrier #25 is generated. In addition, “from time $12 totime $14”, carrier #1 to carrier #25 are divided into three groups togenerate three carrier groups.

The method for dividing frequencies is not limited to the method in FIG.74 . The frequencies allocated to a certain user may serve as onecarrier group, or two or more carrier groups may be generated. Inaddition, it is sufficient that the number of carriers constituting acarrier group be one or more.

According to the description given above using FIG. 74 , “carrier #1 tocarrier #25 and time $1 to time $14 are used by the base station or APto transmit data to a certain terminal (certain user) (terminal #p)”.Alternatively, carrier #1 to carrier #25 and time $1 to time $14 may beallocated for transmitting data to multiple terminals (multiple users)by the base station or AP. Hereinafter, this point will be described.The settings for each carrier group of the precoding matrix Fp(i) are asdescribed above, and thus the description thereof is omitted.

For example, as a first example, in FIG. 74 , terminal allocation (userallocation) may be performed by using time division.

For example, it is assumed that the base station or AP transmits data tothe terminal (user) p1 (i.e., p=p1) by using “time $1 to time #3”. Also,it is assumed that the base station or AP transmits data to the terminal(user) p2 (i.e., p=p2) by using “time $4 to time #9”. It is assumed thatthe base station or AP transmits data to the terminal (user) p3 (i.e.,p=p3) by using “time $10 to time $11”. It is assumed that the basestation or AP transmits data to the terminal (user) p4 (i.e., p=p4) byusing “time $12 to time $14”.

As a second example, in FIG. 74 , terminal allocation (user allocation)may be performed by using frequency division.

For example, it is assumed that the base station or AP transmits data tothe terminal (user) p1 (i.e., p=p1) by using the first carrier group_1and the second carrier group_1. Also, it is assumed that the basestation or AP transmits data to the terminal (user) p2 (i.e., p=p2) byusing the third carrier group_1, the fourth carrier group_1, and thefifth carrier group_1.

As a third example, in FIG. 74 , terminal allocation (user allocation)may be performed by using both time division and frequency division.

For example, it is assumed that the base station or AP transmits data tothe terminal (user) p1 (i.e., p=p1) by using the first carrier group_1,the first carrier group_2, the second carrier group_1, and the secondcarrier group_2. Also, it is assumed that the base station or APtransmits data to the terminal (user) p2 (i.e., p=p2) by using the thirdcarrier group_1, the fourth carrier group_1, and the fifth carriergroup_1. It is assumed that the base station or AP transmits data to theterminal (user) p3 (i.e., p=p3) by using the third carrier group_2 andthe fourth carrier group_2. It is assumed that the base station or APtransmits data to the terminal (user) p4 (i.e., p=p4) by using the fifthcarrier group_2. It is assumed that the base station or AP transmitsdata to the terminal (user) p5 (i.e., p=p5) by using the first carriergroup_3. It is assumed that the base station or AP transmits data to theterminal (user) p6 (i.e., p=p6) by using the first carrier group_4. Itis assumed that the base station or AP transmits data to the terminal(user) p7 (i.e., p=p7) by using the second carrier group_4 and the thirdcarrier group_4.

In the description given above, the method for configuring carriergroups is not limited to FIG. 74 . For example, the number of carriersconstituting a carrier group is not specified as long as the number isone or more. In addition, the time interval for configuring carriergroups is not limited to the configuration in FIG. 74 . In addition, thefrequency division method, the time division method, and the time andfrequency division method for user allocation are not limited to theexamples described above, and any type of division may be used to carryout the embodiment.

In accordance with the above examples, by “changing the precoding matrixperiodically or regularly”, which is processing equivalent to “changingthe phase periodically or regularly” described in the first to fifteenthembodiments, the first to fourth supplements, and so forth, the effectsdescribed in the first to fifteenth embodiments, the first to fourthsupplements, and so forth can be obtained.

Eighteenth Embodiment

The first embodiment, the third embodiment, and so forth describe phasechange before precoding (weight combining) and/or phase change afterprecoding (weight combining), that is, switching between perform and notperform phase change in the phase changer 305B, the phase changer 305A,the phase changer 309A, the phase changer 3801B, and the phase changer3801A in FIGS. 3, 4, 26, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 52, and so forth.

The first embodiment, the second supplement, and so forth describeswitching between perform and not perform phase change in the phasechanger 309B in FIGS. 3, 4, 26, 38, 39 , and so forth (switching betweenperform and not perform CDD (CSD) processing). Obviously, switchingbetween perform and not perform phase change (switching between performand not perform CDD (CSD) processing) may be performed in the phasechanger 309A in FIGS. 75 and 77 .

In the present embodiment, a supplemental description will be given ofthis point.

The first embodiment, the third embodiment, and so forth describe phasechange before precoding (weight combining) and/or phase change afterprecoding (weight combining), that is, switching between perform and notperform phase change in the phase changer 305B, the phase changer 305A,the phase changer 309A, the phase changer 3801B, and the phase changer3801A in FIGS. 3, 4, 26, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 52, and so forth. This phase change is described as the operation of theuser #p signal processor 102_p in FIGS. 1 and 70 .

Thus, in the signal processor for each user, “selection of performing ornot performing phase change in the phase changer 305B, the phase changer305A, the phase changer 309A, the phase changer 3801B, and the phasechanger 3801A in FIGS. 3, 4, 26, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47,48, 52 , and so forth” is performed. That is, in the user #p signalprocessor 102_p (p is 1 to M) in FIGS. 1 and 70 , “selection ofperforming or not performing phase change in the phase changer 305B, thephase changer 305A, the phase changer 309A, the phase changer 3801B, andthe phase changer 3801A in FIGS. 3, 4, 26, 38, 39, 40, 41, 42, 43, 44,45, 46, 47, 48, 52 , and so forth” is performed individually.

The first embodiment, the second supplement, and so forth describeswitching between perform and not perform phase change (switchingbetween perform and not perform CDD (CSD) processing) in the phasechanger 309B in FIGS. 3, 4, 26, 38, 39 , and so forth. Obviously,switching between perform and not perform phase change (switchingbetween perform and not perform CDD (CSD) processing) in the phasechanger 309A in FIGS. 75 and 77 is described. The processing isdescribed as the operation of the user #p signal processor 102_p inFIGS. 1 and 70 .

Thus, in the signal processor for each user, “selection of performing ornot performing phase change (selection of performing or not performingCDD (CSD) processing) in the phase changer 309B in FIGS. 3, 4, 26, 38,39 , and so forth” and/or “selection of performing or not performingphase change (selection of performing or not performing CDD (CSD)processing) in the phase changer 309A in FIGS. 75 and 77 ” is performed.That is, in the user #p signal processor 102_p (p is 1 to M) in FIGS. 1and 70 , “selection of performing or not performing phase change(selection of performing or not performing CDD (CSD) processing) in thephase changer 309B in FIGS. 3, 4, 26, 38, 39 , and so forth” and/or“selection of performing or not performing phase change (selection ofperforming or not performing CDD (CSD) processing) in the phase changer309A in FIGS. 75 and 77 ” is performed individually.

In addition, the first embodiment and the third embodiment describe thatthe base station or AP transmits “information indicating whether or notphase change is performed in the phase changer 305B, the phase changer305A, the phase changer 309A, the phase changer 3801B, and the phasechanger 3801A in FIGS. 3, 4, 26, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47,48, 52 , and so forth” by using the control information symbols includedin the other symbols 603 and 703 in FIGS. 8 and 9 , for example, andalso describe that the base station or AP transmits “informationindicating whether or not phase change is performed in the phase changer305B, the phase changer 305A, the phase changer 309A, the phase changer3801B, and the phase changer 3801A in FIGS. 3, 4, 26, 38, 39, 40, 41,42, 43, 44, 45, 46, 47, 48, 52 , and so forth” by using the preambles1001 and 1101 and the control information symbols 1002 and 1102 in FIGS.10 and 11 , for example.

In the present embodiment, a supplemental description will be given ofthis point.

For example, it is assumed that the base station or AP transmitsmodulated signals addressed to the user #p by using the frameconfigurations in FIGS. 8 and 9 . As an example, it is assumed thatmodulated signals of multiple streams are transmitted.

At this time, it is assumed that the control information symbolsincluded in the other symbols 603 and 703 in FIGS. 8 and 9 include“information indicating whether or not phase change is performed” A601and/or “information indicating whether or not phase change is performed(information indicating whether or not CDD (CSD) processing isperformed)” A602 illustrated in FIG. 78 .

The “information indicating whether or not phase change is performed”A601 is information indicating “whether or not phase change has beenperformed in the phase changer 305B, the phase changer 305A, the phasechanger 309A, the phase changer 3801B, and the phase changer 3801A inFIGS. 3, 4, 26, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 52 , and soforth” in the base station or AP. The terminal as the user #p obtainsthe “information indicating whether or not phase change is performed”A601, thereby performing demodulation/decoding of the data symbols ofthe user #p modulated signals transmitted by the base station or AP.

The “information indicating whether or not phase change is performed(information indicating whether or not CDD (CSD) processing isperformed)” A602 is information indicating “whether or not phase changehas been performed (whether or not CDD (CSD) processing has beenperformed) in the phase changer 309A and the phase changer 309B in FIGS.3, 4, 26, 38, 39, 75, 77 , and so forth” in the base station or AP. Theterminal as the user #p obtains the “information indicating whether ornot phase change is performed (information indicating whether or not CDD(CSD) processing is performed)” A602, thereby performingdemodulation/decoding of the data symbols of the user #p modulatedsignals transmitted by the base station or AP.

The “information indicating whether or not phase change is performed”A601 may be generated for each user. That is, for example, “informationindicating whether or not phase change is performed” A601 addressed tothe user #1, “information indicating whether or not phase change isperformed” A601 addressed to the user #2, “information indicatingwhether or not phase change is performed” A601 addressed to the user #3,may exist. The “information indicating whether or not phase change isperformed” A601 need not necessarily be generated for each user.

Likewise, the “information indicating whether or not phase change isperformed (information indicating whether or not CDD (CSD) processing isperformed)” A602 may be generated for each user. That is, “informationindicating whether or not phase change is performed (informationindicating whether or not CDD (CSD) processing is performed)” A602addressed to the user #1, “information indicating whether or not phasechange is performed (information indicating whether or not CDD (CSD)processing is performed)” A602 addressed to the user #2, “informationindicating whether or not phase change is performed (informationindicating whether or not CDD (CSD) processing is performed)” A602addressed to the user #3, may exist. The “information indicating whetheror not phase change is performed (information indicating whether or notCDD (CSD) processing is performed)” A602 need not necessarily begenerated for each user.

In FIG. 78 , a description has been given of an example in which thecontrol information symbols include both the “information indicatingwhether or not phase change is performed” A601 and the “informationindicating whether or not phase change is performed (informationindicating whether or not CDD (CSD) processing is performed)” A602, buta configuration including either of them may be used.

Next, it is assumed that the base station or AP transmits modulatedsignals addressed to the user #p by using the frame configurations inFIGS. 10 and 11 . As an example, a description will be given of the caseof transmitting modulated signals of multiple streams.

At this time, it is assumed that the preambles 1001 and 1101 and thecontrol information symbols 1002 and 1102 in FIGS. 10 and 11 include the“information indicating whether or not phase change is performed” A601and/or the “information indicating whether or not phase change isperformed (information indicating whether or not CDD (CSD) processing isperformed)” A602 illustrated in FIG. 78 .

The “information indicating whether or not phase change is performed”A601 is information indicating “whether or not phase change has beenperformed in the phase changer 305B, the phase changer 305A, the phasechanger 309A, the phase changer 3801B, and the phase changer 3801A inFIGS. 3, 4, 26, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 52 , and soforth” in the base station or AP. The terminal as the user #p obtainsthe “information indicating whether or not phase change is performed”A601, thereby performing demodulation/decoding of the data symbols ofthe user #p modulated signals transmitted by the base station or AP.

The “information indicating whether or not phase change is performed(information indicating whether or not CDD (CSD) processing isperformed)” A602 is information indicating “whether or not phase changehas been performed (whether or not CDD (CSD) processing has beenperformed) in the phase changer 309A and the phase changer 309B in FIGS.3, 4, 26, 38, 39, 75, 77 , and so forth” in the base station or AP. Theterminal as the user #p obtains the “information indicating whether ornot phase change is performed (information indicating whether or not CDD(CSD) processing is performed)” A602, thereby performingdemodulation/decoding of the data symbols of the user #p modulatedsignals transmitted by the base station or AP.

The “information indicating whether or not phase change is performed”A601 may be generated for each user. That is, for example, “informationindicating whether or not phase change is performed” A601 addressed tothe user #1, “information indicating whether or not phase change isperformed” A601 addressed to the user #2, “information indicatingwhether or not phase change is performed” A601 addressed to the user #3,may exist. The “information indicating whether or not phase change isperformed” A601 need not necessarily be generated for each user.

Likewise, the “information indicating whether or not phase change isperformed (information indicating whether or not CDD (CSD) processing isperformed)” A602 may be generated for each user. That is, “informationindicating whether or not phase change is performed (informationindicating whether or not CDD (CSD) processing is performed)” A602addressed to the user #1, “information indicating whether or not phasechange is performed (information indicating whether or not CDD (CSD)processing is performed)” A602 addressed to the user #2, “informationindicating whether or not phase change is performed (informationindicating whether or not CDD (CSD) processing is performed)” A602addressed to the user #3, may exist. The “information indicating whetheror not phase change is performed (information indicating whether or notCDD (CSD) processing is performed)” A602 need not necessarily begenerated for each user.

In FIG. 78 , a description has been given of an example in which thecontrol information symbols include both the “information indicatingwhether or not phase change is performed” A601 and the “informationindicating whether or not phase change is performed (informationindicating whether or not CDD (CSD) processing is performed)” A602, buta configuration including either of them may be used.

Next, the operation of the reception apparatus will be described.

The configuration and the operation of the reception apparatus have beendescribed in the first embodiment by using FIG. 19 , and thus thedescription given in the first embodiment is omitted here.

The control information decoder 1909 in FIG. 19 obtains the informationin FIG. 78 included in an input signal and outputs the controlinformation signal 1901 including the information.

On the basis of the information in FIG. 78 included in the controlinformation signal 1901, the signal processor 1911 demodulates anddecodes data symbols, and obtains and outputs the reception data 1912.

As a result of carrying out the embodiment in the above-describedmanner, the effects described in this specification can be obtained.

Nineteenth Embodiment

In the first to fifteenth embodiments, the first to fourth supplements,and so forth, when both “the phase changer 305B, the phase changer 305A,the phase changer 309A, the phase changer 3801B, and the phase changer3801A in FIGS. 3, 4, 26, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 52, and so forth” and the computation in the weight combiner 303 areconsidered together, for example, this corresponds to switching of theprecoding matrix by i when consideration is given with reference toExpression (37), Expression (42), Expression (49), Expression (51),Expression (64), and Expression (65), for example.

In addition, in a case where Expression (21), Expression (22),Expression (23), Expression (24), Expression (25), Expression (26),Expression (27), and Expression (28) are used in the weight combiner303, for example, this corresponds to switching of the precoding matrixby i.

This point has been described in the seventeenth embodiment, and FIGS.76 and 77 illustrate the configurations of the user #p signal processor102_p in FIGS. 1 and 70 .

In the present embodiment, a description will be given of switchingbetween perform and not perform change of the precoding matrix in theweight combiner A401 in FIGS. 76 and 77 , which is an operation similarto that in the seventeenth embodiment.

FIGS. 76 and 77 described in the seventeenth embodiment correspond tothe user #p signal processor 102_p in FIGS. 1 and 70 . Thus, in thesignal processor for each user, selection of performing or notperforming change of the precoding matrix is performed by the weightcombiner A401. That is, in the user #p signal processor 102_p (p is 1 toM) in FIGS. 1 and 70 , selection of performing or not performing changeof the precoding matrix is performed individually by the weight combinerA401.

For example, it is assumed that the base station or AP transmitsmodulated signals addressed to the user #p by using the frameconfigurations in FIGS. 8 and 9 . As an example, it is assumed thatmodulated signals of multiple streams are transmitted.

At this time, it is assumed that the control information symbolsincluded in the other symbols 603 and 703 in FIGS. 8 and 9 include“information indicating whether or not precoding matrix change isperformed” A701 and/or the “information indicating whether or not phasechange is performed (information indicating whether or not CDD (CSD)processing is performed)” A602 illustrated in FIG. 79 .

The “information indicating whether or not precoding matrix change isperformed” A701 is information indicating “whether or not precodingmatrix change is performed in the weight combiner A401 in FIGS. 76 and77 ” in the base station or AP. The terminal as the user #p obtains the“information indicating whether or not precoding matrix change isperformed” A701, thereby performing demodulation/decoding of the datasymbols of the user #p modulated signals transmitted by the base stationor AP.

The “information indicating whether or not phase change is performed(information indicating whether or not CDD (CSD) processing isperformed)” A602 is information indicating “whether or not phase changehas been performed (whether or not CDD (CSD) processing has beenperformed) in the phase changer 309A and the phase changer 309B in FIGS.76, 77 , and so forth” in the base station or AP. The terminal as theuser #p obtains the “information indicating whether or not phase changeis performed (information indicating whether or not CDD (CSD) processingis performed)” A602, thereby performing demodulation/decoding of thedata symbols of the user #p modulated signals transmitted by the basestation or AP.

The “information indicating whether or not precoding matrix change isperformed” A701 may be generated for each user. That is, for example,“information indicating whether or not precoding matrix change isperformed” A701 addressed to the user #1, “information indicatingwhether or not precoding matrix change is performed” A701 addressed tothe user #2, “information indicating whether or not precoding matrixchange is performed” A701 addressed to the user #3, may exist. The“information indicating whether or not precoding matrix change isperformed” A701 need not necessarily be generated for each user.

Likewise, the “information indicating whether or not phase change isperformed (information indicating whether or not CDD (CSD) processing isperformed)” A602 may be generated for each user. That is, “informationindicating whether or not phase change is performed (informationindicating whether or not CDD (CSD) processing is performed)” A602addressed to the user #1, “information indicating whether or not phasechange is performed (information indicating whether or not CDD (CSD)processing is performed)” A602 addressed to the user #2, “informationindicating whether or not phase change is performed (informationindicating whether or not CDD (CSD) processing is performed)” A602addressed to the user #3, may exist. The “information indicating whetheror not phase change is performed (information indicating whether or notCDD (CSD) processing is performed)” A602 need not necessarily begenerated for each user.

In FIG. 79 , a description has been given of an example in which thecontrol information symbols include both the “information indicatingwhether or not precoding matrix change is performed” A701 and the“information indicating whether or not phase change is performed(information indicating whether or not CDD (CSD) processing isperformed)” A602, but a configuration including either of them may beused.

Next, it is assumed that the base station or AP transmits modulatedsignals addressed to the user #p by using the frame configurations inFIGS. 10 and 11 . As an example, a description will be given of the caseof transmitting modulated signals of multiple streams.

At this time, it is assumed that the preambles 1001 and 1101 and thecontrol information symbols 1002 and 1102 in FIGS. 10 and 11 include the“information indicating whether or not precoding matrix change isperformed” A701 and/or the “information indicating whether or not phasechange is performed (information indicating whether or not CDD (CSD)processing is performed)” A602 illustrated in FIG. 79 .

The “information indicating whether or not precoding matrix change isperformed” A701 is information indicating “whether or not precodingmatrix change is performed in the weight combiner A401 in FIGS. 76 and77 ” in the base station or AP. The terminal as the user #p obtains the“information indicating whether or not precoding matrix change isperformed” A701, thereby performing demodulation/decoding of the datasymbols of the user #p modulated signals transmitted by the base stationor AP.

The “information indicating whether or not phase change is performed(information indicating whether or not CDD (CSD) processing isperformed)” A602 is information indicating “whether or not phase changehas been performed (whether or not CDD (CSD) processing has beenperformed) in the phase changer 309A and the phase changer 309B in FIGS.76, 77 , and so forth” in the base station or AP. The terminal as theuser #p obtains the “information indicating whether or not phase changeis performed (information indicating whether or not CDD (CSD) processingis performed)” A602, thereby performing demodulation/decoding of thedata symbols of the user #p modulated signals transmitted by the basestation or AP.

The “information indicating whether or not precoding matrix change isperformed” A701 may be generated for each user. That is, for example,“information indicating whether or not precoding matrix change isperformed” A701 addressed to the user #1, “information indicatingwhether or not precoding matrix change is performed” A701 addressed tothe user #2, “information indicating whether or not precoding matrixchange is performed” A701 addressed to the user #3, may exist. The“information indicating whether or not precoding matrix change isperformed” A701 need not necessarily be generated for each user.

Likewise, the “information indicating whether or not phase change isperformed (information indicating whether or not CDD (CSD) processing isperformed)” A602 may be generated for each user. That is, “informationindicating whether or not phase change is performed (informationindicating whether or not CDD (CSD) processing is performed)” A602addressed to the user #1, “information indicating whether or not phasechange is performed (information indicating whether or not CDD (CSD)processing is performed)” A602 addressed to the user #2, “informationindicating whether or not phase change is performed (informationindicating whether or not CDD (CSD) processing is performed)” A602addressed to the user #3, may exist. The “information indicating whetheror not phase change is performed (information indicating whether or notCDD (CSD) processing is performed)” A602 need not necessarily begenerated for each user.

In FIG. 79 , a description has been given of an example in which thecontrol information symbols include both the “information indicatingwhether or not precoding matrix change is performed” A701 and the“information indicating whether or not phase change is performed(information indicating whether or not CDD (CSD) processing isperformed)” A602, but a configuration including either of them may beused.

Next, the operation of the reception apparatus will be described.

The configuration and the operation of the reception apparatus have beendescribed in the first embodiment by using FIG. 19 , and thus thedescription given in the first embodiment is omitted here.

The control information decoder 1909 in FIG. 19 obtains the informationin FIG. 79 included in an input signal and outputs the controlinformation signal 1901 including the information.

On the basis of the information in FIG. 79 included in the controlinformation signal 1901, the signal processor 1911 demodulates anddecodes data symbols, and obtains and outputs the reception data 1912.

As a result of carrying out the embodiment in the above-describedmanner, the effects described in this specification can be obtained.

Fifth Supplement

Although not illustrated in FIGS. 3, 4, 26, 38, 39, 75, 76 and so forth,the pilot symbol signal (pa(t)) (351A), the pilot symbol signal (pb(t))(351B), the preamble signal 352, and the control information symbolsignal 353 may be signals that have been subjected to processing such asphase change.

Twentieth Embodiment

In the present embodiment, a description will be given of another methodfor carrying out the operation of the terminal #p that has beendescribed in the third embodiment, the fifth embodiment, the fifteenthembodiment, and so forth.

The base station or AP has the configuration illustrated in FIG. 22 ,for example, and receives a signal transmitted by the terminal #p. Theconfiguration in FIG. 22 has already been described, and thus thedescription thereof is omitted.

FIG. 34 is an example of the configuration of the terminal #p, which isa communication partner of the base station or AP. The description hasalready been given, and thus the description is omitted.

FIG. 27 illustrates an example of communication between the base stationor AP and the terminal #p. The details thereof have been described inthe third embodiment, the fifth embodiment, the fifteenth embodiment,and so forth, and thus the description thereof is omitted.

FIG. 80 illustrates a specific example configuration of the receptioncapability notification symbol 2702 transmitted by the terminal #pillustrated in FIG. 27 .

Before describing FIG. 80 , a description will be given of theconfiguration of the terminal #p that exists as the terminal #p thatcommunicates with the base station or AP.

In the present embodiment, it is assumed that the following types ofterminals #p may exist.

Terminal Type #1:

It is possible to demodulate a modulated signal of the single-carrierscheme and single-stream transmission.

Terminal Type #2:

It is possible to demodulate a modulated signal of the single-carrierscheme and single-stream transmission. Additionally, it is possible toreceive and demodulate multiple modulated signals of the single-carrierscheme transmitted by a communication partner by using multipleantennas.

Terminal Type #3:

It is possible to demodulate a modulated signal of the single-carrierscheme and single-stream transmission. Furthermore, it is possible todemodulate a modulated signal of the OFDM scheme and single-streamtransmission.

Terminal Type #4:

It is possible to demodulate a modulated signal of the single-carrierscheme and single-stream transmission. Additionally, it is possible toreceive and demodulate multiple modulated signals of the single-carrierscheme transmitted by a communication partner by using multipleantennas. Furthermore, it is possible to demodulate a modulated signalof the OFDM scheme and single-stream transmission. Additionally, it ispossible to receive and demodulate multiple modulated signals of theOFDM scheme transmitted by a communication partner by using multipleantennas.

Terminal Type #5:

It is possible to demodulate a modulated signal of the OFDM scheme andsingle-stream transmission.

Terminal Type #6:

It is possible to demodulate a modulated signal of the OFDM scheme andsingle-stream transmission. Additionally, it is possible to receive anddemodulate multiple modulated signals of the OFDM scheme transmitted bya communication partner by using multiple antennas.

In the present embodiment, for example, it is assumed that the terminals#p of the terminal type #1 to the terminal type #6 may communicate withthe base station or AP. Note that the base station or AP may communicatewith the terminal #p of a type different from the terminal type #1 tothe terminal type #6.

In view of the above, the reception capability notification symbol inFIG. 80 will be described.

FIG. 80 illustrates an example of a specific configuration of thereception capability notification symbol 2702 transmitted by theterminal #p illustrated in FIG. 27 .

As illustrated in FIG. 80 , a “single-carrier scheme and OFDM schemerelated reception capability notification symbol 9401”, a“single-carrier scheme related reception capability notification symbol9402”, and an “OFDM scheme related reception capability notificationsymbol 9403” constitute a reception capability notification symbol. Areception capability notification symbol other than those illustrated inFIG. 80 may be included.

It is assumed that the “single-carrier scheme and OFDM scheme relatedreception capability notification symbol 9401” includes data fornotifying a communication partner (in this case, for example, the basestation or AP) of the reception capability for both a modulated signalof the single-carrier scheme and a modulated signal of the OFDM scheme.

Also, it is assumed that the “single-carrier scheme related receptioncapability notification symbol 9402” includes data for notifying acommunication partner (in this case, for example, the base station orAP) of the reception capability for a modulated signal of thesingle-carrier scheme.

It is assumed that the “OFDM scheme related reception capabilitynotification symbol 9403” includes data for notifying a communicationpartner (in this case, for example, the base station or AP) of thereception capability for a modulated signal of the OFDM scheme.

FIG. 81 illustrates an example of the configuration of the“single-carrier scheme and OFDM scheme related reception capabilitynotification symbol 9401” illustrated in FIG. 80 .

It is assumed that the “single-carrier scheme and OFDM scheme relatedreception capability notification symbol 9401” illustrated in FIG. 80includes data 9501 about “support of SISO or MIMO (MISO)”, data 9502about “supported error-correcting coding schemes”, and data 9503 about“support status of single-carrier scheme and OFDM scheme” in FIG. 81 .

When the data 9501 about “support of SISO or MIMO (MISO)” is g0 and g1,the terminal #p performs the following operation, for example.

For example, it is assumed that, in a case where the communicationpartner of the terminal #p transmits a modulated signal of a singlestream and the terminal #p is able to demodulate the modulated signal,the terminal #p sets g0=1 and g1=0, and the terminal #p transmits areception capability notification symbol including g0 and g1.

It is assumed that, in a case where the communication partner of theterminal #p transmits multiple different modulated signals by usingmultiple antennas and the terminal #p is able to demodulate themodulated signals, the terminal #p sets g0=0 and g1=1, and the terminal#p transmits a reception capability notification symbol including g0 andg1.

It is assumed that, in a case where the communication partner of theterminal #p transmits a modulated signal of a single stream and theterminal #p is able to demodulate the modulated signal, and in a casewhere the communication partner of the terminal #p transmits multipledifferent modulated signals by using multiple antennas and the terminal#p is able to demodulate the modulated signals, the terminal #p setsg0=1 and g1=1, and the terminal #p transmits a reception capabilitynotification symbol including g0 and g1.

When the data 9502 about “supported error-correcting coding schemes” isg2, the terminal #p performs the following operation, for example.

For example, it is assumed that, in a case where the terminal #p is ableto perform error-correcting decoding on data of a first error-correctingcoding scheme, the terminal #p sets g2=0, and the terminal #p transmitsa reception capability notification symbol including g2.

It is assumed that, in a case where the terminal #p is able to performerror-correcting decoding on data of the first error-correcting codingscheme and is able to perform error-correcting decoding on data of asecond error-correcting coding scheme, the terminal #p sets g2=1, andthe terminal #p transmits a reception capability notification symbolincluding g2.

As another case, it is assumed that each terminal #p is able to performerror-correcting decoding on data of the first error-correcting codingscheme. Furthermore, in a case where the terminal #p is able to performerror-correcting decoding on data of the second error-correcting codingscheme, the terminal #p sets g2=1, and in a case where the terminal #pdoes not support error-correcting decoding on data of the seconderror-correcting coding scheme, the terminal #p sets g2=0. It is assumedthat the terminal #p transmits a reception capability notificationsymbol including g2.

It is assumed that the first error-correcting coding scheme and thesecond error-correcting coding scheme are different schemes. Forexample, it is assumed that the block length (code length) of the firsterror-correcting coding scheme is A bits (A is an integer equal to orgreater than 2), the block length (code length) of the seconderror-correcting coding scheme is B bits (B is an integer equal to orgreater than 2), and A≠B holds. However, an example of the differentschemes is not limited thereto, and the error-correcting code used inthe first error-correcting coding scheme and the error-correcting codeused in the second error-correcting coding scheme may be different fromeach other.

When the data 9503 about “support status of single-carrier scheme andOFDM scheme” is g3 and g4, the terminal #p performs the followingoperation, for example.

For example, it is assumed that, in a case where the terminal #p is ableto demodulate a modulated signal of the single-carrier scheme, theterminal #p sets g3=1 and g4=0 (in this case, the terminal #p does notsupport demodulation of a modulated signal of OFDM), and the terminal #ptransmits a reception capability notification symbol including g3 andg4.

It is assumed that, in a case where the terminal #p is able todemodulate a modulated signal of the OFDM scheme, the terminal #p setsg3=0 and g4=1 (in this case, the terminal #p does not supportdemodulation of a modulated signal of the single-carrier scheme), andthe terminal #p transmits a reception capability notification symbolincluding g3 and g4.

It is assumed that, in a case where the terminal #p is able todemodulate a modulated signal of the single-carrier scheme and is ableto demodulate a modulated signal of the OFDM scheme, the terminal #psets g3=1 and g4=1, and the terminal #p transmits a reception capabilitynotification symbol including g3 and g4.

FIG. 82 illustrates an example of the configuration of the“single-carrier scheme related reception capability notification symbol9402” illustrated in FIG. 80 .

It is assumed that the “single-carrier scheme related receptioncapability notification symbol 9402” illustrated in FIG. 80 includesdata 9601 about “schemes supported by single-carrier scheme” in FIG. 82.

When the data 9601 about “schemes supported by single-carrier scheme” ish0 and h1, the terminal #p performs the following operation, forexample.

For example, it is assumed that, in a case where the communicationpartner of the terminal #p transmits a modulated signal by performingchannel bonding and the terminal #p is able to demodulate the modulatedsignal, the terminal #p sets h0=1, whereas in a case where the terminal#p does not support demodulation of the modulated signal, the terminal#p sets h0=0, and the terminal #p transmits a reception capabilitynotification symbol including h0.

It is assumed that, in a case where the communication partner of theterminal #p transmits a modulated signal by performing channelaggregation and the terminal #p is able to demodulate the modulatedsignal, the terminal #p sets h1=1, whereas in a case where the terminal#p does not support demodulation of the modulated signal, the terminal#p sets h1=0, and the terminal #p transmits a reception capabilitynotification symbol including h1.

In a case where the terminal #p sets g3 to 0 and g4 to 1, since theterminal #p does not support demodulation of a modulated signal of thesingle-carrier scheme, the bit (field) of h0 is an invalid bit (field),and also the bit (field) of h1 is an invalid bit (field).

In a case where the terminal #p sets g3 to 0 and g4 to 1, the above h0and h1 may be regarded as a reserved (maintained for the future) bit(field) according to the prescription given in advance, or the terminal#p may determine the above h0 and h1 to be an invalid bit (field) (maydetermine the above h0 or h1 to be an invalid bit (field)), or the basestation or AP may obtain the above h0 and h1 and determine h0 and h1 tobe an invalid bit (field) (may determine the above h0 or h1 to be aninvalid bit (field)).

According to the description given above, there is a case where theterminal #p sets g3 to 0 and g4 to 1, that is, a case where the terminal#p does not support demodulation of a modulated signal of thesingle-carrier scheme, but an embodiment is possible in which eachterminal #p “supports the demodulation of the single-carrier scheme”. Inthis case, the bit (field) of g3 described above is not necessary.

FIG. 83 illustrates an example of the configuration of the “OFDM schemerelated reception capability notification symbol 9403” illustrated inFIG. 80 .

It is assumed that the “OFDM scheme related reception capabilitynotification symbol 9403” illustrated in FIG. 80 includes data 9701about “schemes supported by OFDM scheme” in FIG. 83 .

In addition, it is assumed that the data 9701 about “schemes supportedby OFDM scheme” includes the data 2801 about “support/not supportdemodulation of modulated signal with phase change” illustrated in FIGS.28, 30, 71 , and so forth. The data 2801 about “support/not supportdemodulation of modulated signal with phase change” has been describedin the third embodiment, the fifth embodiment, the fifteenth embodiment,and so forth, and thus the detailed description thereof is omitted.

When the data 2801 about “support/not support demodulation of modulatedsignal with phase change” is k0, the terminal #p performs the followingoperation, for example.

For example, assume a case where the communication partner of theterminal #p generates multiple modulated signals by performing phasechange processing and transmits the generated multiple modulated signalsby using multiple antennas. In this case, it is assumed that, in a casewhere the terminal #p is able to demodulate the modulated signals, theterminal #p sets k0=1, whereas in a case where the terminal #p does notsupport demodulation of the modulated signals, the terminal #p setsk0=0, and the terminal #p transmits a reception capability notificationsymbol including k0.

In a case where the terminal #p sets g3 to 1 and g4 to 0, since theterminal #p does not support demodulation of a modulated signal of theOFDM scheme, the bit (field) of k0 is an invalid bit (field).

In a case where the terminal #p sets g3 to 1 and g4 to 0, the above k0may be regarded as a reserved (maintained for the future) bit (field)according to the prescription given in advance, or the terminal #p maydetermine the above k0 to be an invalid bit (field), or the base stationor AP may obtain the above k0 and determine k0 to be an invalid bit(field).

In the description given above, an embodiment is possible in which eachterminal #p “supports the demodulation of the single-carrier scheme”. Inthis case, the bit (field) of g3 described above is not necessary.

The base station that has received the reception capability notificationsymbol transmitted by the terminal #p described above generates andtransmits a modulated signal on the basis of the reception capabilitynotification symbol, and accordingly the terminal #p is able to receivea transmission signal that can be demodulated. A specific example of theoperation of the base station has been described in embodiments, such asthe third embodiment, the fifth embodiment, and the fifteenthembodiment.

With the embodiment being carried out in the above-described manner, thefollowing example characteristics can be obtained.

Characteristic #1

-   -   “A first reception apparatus, where    -   the reception apparatus generates control information indicating        a signal receivable by the reception apparatus, the control        information including a first region, a second region, a third        region, and a fourth region,    -   the first region is a region storing information indicating        whether or not it is possible to receive a signal for        transmitting data generated by using a single-carrier scheme and        information indicating whether or not it is possible to receive        a signal generated by using a multi-carrier scheme,    -   the second region is a region storing information indicating        whether or not it is possible to receive a signal generated by        using any one of one or more schemes usable in both or either of        a case of generating a signal by using the single-carrier scheme        and a case of generating a signal by using the multi-carrier        scheme,    -   the third region is    -   in a case of storing, in the first region, information        indicating that it is possible to receive a signal for        transmitting data generated by using the single-carrier scheme,        a region storing information indicating whether or not it is        possible to receive a signal generated by using any one of one        or more schemes usable in a case of generating a signal by using        the single-carrier scheme, and    -   in a case of storing, in the first region, information        indicating that it is impossible to receive a signal for        transmitting data generated by using the single-carrier scheme,        an invalid or reserved region,    -   the fourth region is    -   in a case of storing, in the first region, information        indicating that it is possible to receive a signal for        transmitting data generated by using the multi-carrier scheme, a        region storing information indicating whether or not it is        possible to receive a signal generated by using any one of one        or more schemes usable in a case of generating a signal by using        the multi-carrier scheme, and    -   in a case of storing, in the first region, information        indicating that it is impossible to receive a signal for        transmitting data generated by using the multi-carrier scheme,        an invalid or reserved region, and    -   the reception apparatus generates a control signal from the        control information and transmits the control signal to a        transmission apparatus.”

“The above-described first reception apparatus, where

-   -   the second region includes a fifth region storing information        indicating whether or not it is possible to receive a signal        generated by using the Multiple-Input Multiple-Output (MIMO)        scheme,    -   the second region or the fourth region includes a sixth region        storing information indicating whether or not it is possible to        receive a signal generated by using a phase change scheme for        performing phase change while regularly switching a phase change        value with respect to at least any one of signals of multiple        transmission systems for transmitting data, and    -   the reception apparatus sets a bit located in the sixth region        to a predetermined value in a case of storing, in the first        region, information indicating that it is impossible to receive        a signal for transmitting data generated by using the        multi-carrier scheme, or in a case of storing, in the first        region, information indicating that it is possible to receive a        signal for transmitting data generated by using the        multi-carrier scheme and storing, in the fifth region,        information indicating that it is impossible to receive a signal        of the MIMO scheme.”

“A first transmission apparatus that

-   -   receives the control signal from the above-described first        reception apparatus,    -   demodulates the received control signal to obtain the control        signal, and    -   decides, on the basis of the control signal, a scheme to be used        to generate a signal to be transmitted to the reception        apparatus.”

“The above-described first transmission apparatus, where

-   -   the second region includes a fifth region storing information        indicating whether or not it is possible to receive a signal        generated by using the Multiple-Input Multiple-Output (MIMO)        scheme,    -   the second region or the fourth region includes a sixth region        storing information indicating whether or not it is possible to        receive a signal generated by using a phase change scheme for        performing phase change while regularly switching a phase change        value with respect to at least any one of signals of multiple        transmission systems for transmitting data, and    -   the transmission apparatus decides a scheme to be used to        generate a signal to be transmitted to the reception apparatus        without using a value of a bit located in the sixth region in a        case where the first region includes information indicating that        it is impossible to receive a signal for transmitting data        generated by using the multi-carrier scheme, or in a case where        the first region includes information indicating that it is        possible to receive a signal for transmitting data generated by        using the multi-carrier scheme and the fifth region includes        information indicating that it is impossible to receive a signal        of the MIMO scheme.”

Characteristic #2

“A second reception apparatus, where

-   -   the reception apparatus generates control information indicating        a signal receivable by the reception apparatus, the control        information including a first region, a second region, a third        region, and a fourth region,    -   the first region is a region storing information indicating        whether or not it is possible to receive a signal generated by        using a multi-carrier scheme,    -   the second region is a region storing information indicating        whether or not it is possible to receive a signal generated by        using any one of one or more schemes usable in both or either of        a case of generating a signal by using a single-carrier scheme        and a case of generating a signal by using the multi-carrier        scheme,    -   the third region is a region storing information indicating        whether or not it is possible to receive a signal generated by        using any one of one or more schemes usable in a case of        generating a signal by using the single-carrier scheme,    -   the fourth region is    -   in a case of storing, in the first region, information        indicating that it is possible to receive a signal for        transmitting data generated by using the multi-carrier scheme, a        region storing information indicating whether or not it is        possible to receive a signal generated by using any one of one        or more schemes usable in a case of generating a signal by using        the multi-carrier scheme, and    -   in a case of storing, in the first region, information        indicating that it is impossible to receive a signal for        transmitting data generated by using the multi-carrier scheme,        an invalid or reserved region, and    -   the reception apparatus generates a control signal from the        control information and transmits the control signal to a        transmission apparatus.”

“The above-described second reception apparatus, where

-   -   the second region includes a fifth region storing information        indicating whether or not it is possible to receive a signal        generated by using the Multiple-Input Multiple-Output (MIMO)        scheme,    -   the second region or the fourth region includes a sixth region        storing information indicating whether or not it is possible to        receive a signal generated by using a phase change scheme for        performing phase change while regularly switching a phase change        value with respect to at least any one of signals of multiple        transmission systems for transmitting data, and    -   the reception apparatus sets a bit located in the sixth region        to a predetermined value in a case of storing, in the first        region, information indicating that it is impossible to receive        a signal for transmitting data generated by using the        multi-carrier scheme, or in a case of storing, in the first        region, information indicating that it is possible to receive a        signal for transmitting data generated by using the        multi-carrier scheme and storing, in the fifth region,        information indicating that it is impossible to receive a signal        of the MIMO scheme.”

“A second transmission apparatus that

-   -   receives the control signal from the above-described second        reception apparatus,    -   demodulates the received control signal to obtain the control        signal, and    -   decides, on the basis of the control signal, a scheme to be used        to generate a signal to be transmitted to the reception        apparatus.”

“The above-described second transmission apparatus, where

-   -   the second region includes a fifth region storing information        indicating whether or not it is possible to receive a signal        generated by using the Multiple-Input Multiple-Output (MIMO)        scheme,    -   the second region or the fourth region includes a sixth region        storing information indicating whether or not it is possible to        receive a signal generated by using a phase change scheme for        performing phase change while regularly switching a phase change        value with respect to at least any one of signals of multiple        transmission systems for transmitting data, and    -   the transmission apparatus decides a scheme to be used to        generate a signal to be transmitted to the reception apparatus        without using a value of a bit located in the sixth region in a        case where the first region includes information indicating that        it is impossible to receive a signal for transmitting data        generated by using the multi-carrier scheme, or in a case where        the first region includes information indicating that it is        possible to receive a signal for transmitting data generated by        using the multi-carrier scheme and the fifth region includes        information indicating that it is impossible to receive a signal        of the MIMO scheme.”

In the present embodiment, the configuration in FIG. 80 has beendescribed as an example of the configuration of the reception capabilitynotification symbol 2702 in FIG. 27 , but the configuration is notlimited thereto, and a reception capability notification symboldifferent from that in FIG. 80 may exist. For example, the configurationin FIG. 84 may be used.

In FIG. 84 , the elements that operate similarly to those in FIG. 80 aredenoted by the same numerals, and the description thereof is omitted. InFIG. 84 , the other reception capability notification symbol 9801 isadded as a reception capability notification symbol.

The other reception capability notification symbol 9801 is, for example,a reception capability notification symbol that is not the“single-carrier scheme and OFDM scheme related reception capabilitynotification symbol 9401”, that is not the “single-carrier schemerelated reception capability notification symbol 9402”, and that is notthe “OFDM scheme related reception capability notification symbol 9403”.

Also with such a reception capability notification symbol, theabove-described embodiments can be carried out similarly.

In FIG. 80 , a description has been given of an example of the receptioncapability notification symbol in which the “single-carrier scheme andOFDM scheme related reception capability notification symbol 9401”, the“single-carrier scheme related reception capability notification symbol9402”, and the “OFDM scheme related reception capability notificationsymbol 9403” are arranged in this order, but the reception capabilitynotification symbol is not limited thereto. An example thereof will bedescribed below.

In FIG. 80 , it is assumed that bit r0, bit r1, bit r2, and bit r3 existas the “single-carrier scheme and OFDM scheme related receptioncapability notification symbol 9401”. Also, it is assumed that bit r4,bit r5, bit r6, and bit r7 exist as the “single-carrier scheme relatedreception capability notification symbol 9402”. Also, it is assumed thatbit r8, bit r9, bit r10, and bit r11 exist as the “OFDM scheme relatedreception capability notification symbol 9403”.

In the case of FIG. 80 , it is assumed that bit r1, bit r2, bit r3, bitr4, bit r5, bit r6, bit r7, bit r8, bit r9, bit r10, and bit r11 arearranged in order, and are located in this order with respect to aframe, for example.

As another method, a bit sequence in which the order of “bit r1, bit r2,bit r3, bit r4, bit r5, bit r6, bit r7, bit r8, bit r9, bit r10, and bitr11” is changed, for example, a bit sequence of “bit r7, bit r2, bit r4,bit r6, bit r1, bit r8, bit r9, bit r5, bit r10, bit r3, and bit r11”may be located in this order with respect to a frame. The order in thebit sequence is not limited to this example.

In addition, in FIG. 80 , it is assumed that field s0, field s1, fields2, and field s3 exist as the “single-carrier scheme and OFDM schemerelated reception capability notification symbol 9401”. Also, it isassumed that field s4, field s5, field s6, and field s7 exist as the“single-carrier scheme related reception capability notification symbol9402”. Also, it is assumed that field s8, field s9, field s10, and fields11 exist as the “OFDM scheme related reception capability notificationsymbol 9403”. It is assumed that a “field” is made up of one or morebits.

In the case of FIG. 80 , it is assumed that field s1, field s2, fields3, field s4, field s5, field s6, field s7, field s8, field s9, fields10, and field s11 are arranged in order, and are located in this orderwith respect to a frame, for example.

As another method, a field sequence in which the order of “field s1,field s2, field s3, field s4, field s5, field s6, field s7, field s8,field s9, field s10, and field s11” is changed, for example, a fieldsequence of “field s7, field s2, field s4, field s6, field s1, field s8,field s9, field s5, field s10, field s3, and field s11” may be locatedin this order with respect to a frame. The order in the field sequenceis not limited to this example.

In FIG. 84 , a description has been given of an example of the receptioncapability notification symbol in which the “single-carrier scheme andOFDM scheme related reception capability notification symbol 9401”, the“single-carrier scheme related reception capability notification symbol9402”, the “OFDM scheme related reception capability notification symbol9403”, and the “other reception capability notification symbol 9801” arearranged in this order, but the reception capability notification symbolis not limited thereto. An example thereof will be described below.

In FIG. 84 , it is assumed that bit r0, bit r1, bit r2, and bit r3 existas the “single-carrier scheme and OFDM scheme related receptioncapability notification symbol 9401”. Also, it is assumed that bit r4,bit r5, bit r6, and bit r7 exist as the “single-carrier scheme relatedreception capability notification symbol 9402”. Also, it is assumed thatbit r8, bit r9, bit r10, and bit r11 exist as the “OFDM scheme relatedreception capability notification symbol 9403”. Also, it is assumed thatbit r12, bit r13, bit r14, and bit r15 exist as the “other receptioncapability notification symbol 9801”.

In the case of FIG. 84 , it is assumed that bit r1, bit r2, bit r3, bitr4, bit r5, bit r6, bit r7, bit r8, bit r9, bit r10, bit r11, bit r12,bit r13, bit r14, and bit r15 are arranged in order, and are located inthis order with respect to a frame, for example.

As another method, a bit sequence in which the order of “bit r1, bit r2,bit r3, bit r4, bit r5, bit r6, bit r7, bit r8, bit r9, bit r10, bitr11, bit r12, bit r13, bit r14, and bit r15” is changed, for example, abit sequence of “bit r7, bit r2, bit r4, bit r6, bit r13, bit r1, bitr8, bit r12, bit r9, bit r5, bit r10, bit r3, bit r15, bit r11, and bitr14” may be located in this order with respect to a frame. The order inthe bit sequence is not limited to this example.

In addition, in FIG. 84 , it is assumed that field s0, field s1, fields2, and field s3 exist as the “single-carrier scheme and OFDM schemerelated reception capability notification symbol 9401”. Also, it isassumed that field s4, field s5, field s6, and field s7 exist as the“single-carrier scheme related reception capability notification symbol9402”. Also, it is assumed that field s8, field s9, field s10, and fields11 exist as the “OFDM scheme related reception capability notificationsymbol 9403”. Also, it is assumed that field s12, field s13, field s14,and field s15 exist as the “other reception capability notificationsymbol 9801”. It is assumed that a “field” is made up of one or morebits.

In the case of FIG. 84 , it is assumed that field s1, field s2, fields3, field s4, field s5, field s6, field s7, field s8, field s9, fields10, field s11, field s12, field s13, field s14, and field s15 arearranged in order, and are located in this order with respect to aframe, for example.

As another method, a field sequence in which the order of “field s1,field s2, field s3, field s4, field s5, field s6, field s7, field s8,field s9, field s10, field s11, field s12, field s13, field s14, andfield s15” is changed, for example, a field sequence of “field s7, fields2, field s4, field s6, field s13, field s1, field s8, field s12, fields9, field s5, field s10, field s3, field s15, field s1l, and field s14”may be located in this order with respect to a frame. The order in thefield sequence is not limited to this example.

It is not always explicitly indicated that the information transmittedby the “single-carrier scheme related reception capability notificationsymbol” is information directed to the single-carrier scheme. Theinformation transmitted by the “single-carrier scheme related receptioncapability notification symbol” described in the present embodiment is,for example, information for giving a notice about a selectable schemein a case where the transmission apparatus transmits a signal in thesingle-carrier scheme. In another example, the information transmittedby the “single-carrier scheme related reception capability notificationsymbol” described in the present embodiment is, for example, informationthat is not used (ignored) to select a scheme to be used fortransmitting a signal in a case where the transmission apparatustransmits a signal in a scheme other than the single-carrier scheme,such as the OFDM scheme. In still another example, the informationtransmitted by the “single-carrier scheme related reception capabilitynotification symbol” described in the present embodiment is, forexample, information that is transmitted by using a region determined tobe an invalid region or reserved region by the transmission apparatus orthe reception apparatus in a case where the reception apparatus does notsupport the reception of a signal of the single-carrier scheme (notifiesthe transmission apparatus of non-support). In the above description,the term “single-carrier scheme related reception capabilitynotification symbol 9402” is used, but the term is not limited thereto,and another term may be used. For example, the term “symbol indicatingthe reception capability of the (first) terminal #p” may be used. Inaddition, the “single-carrier scheme related reception capabilitynotification symbol 9402” may include information other than informationfor giving a notice about a receivable signal.

Likewise, it is not always explicitly indicated that the informationtransmitted by the “OFDM scheme related reception capabilitynotification symbol” is information directed to the OFDM scheme. Theinformation transmitted by the “OFDM scheme related reception capabilitynotification symbol” described in the present embodiment is, forexample, information for giving a notice about a selectable scheme in acase where the transmission apparatus transmits a signal in the OFDMscheme. In another example, the information transmitted by the “OFDMscheme related reception capability notification symbol” described inthe present embodiment is, for example, information that is not used(ignored) to select a scheme to be used for transmitting a signal in acase where the transmission apparatus transmits a signal in a schemeother than the OFDM scheme, such as the single-carrier scheme. In stillanother example, the information transmitted by the “OFDM scheme relatedreception capability notification symbol” described in the presentembodiment is, for example, information that is transmitted by using aregion determined to be an invalid region or reserved region by thetransmission apparatus or the reception apparatus in a case where thereception apparatus does not support the reception of a signal of theOFDM scheme. In the above description, the term “OFDM scheme relatedreception capability notification symbol 9403” is used, but the term isnot limited thereto, and another term may be used. For example, the term“symbol indicating the reception capability of the (second) terminal #p”may be used. In addition, the “OFDM scheme related reception capabilitynotification symbol 9403” may include information other than informationfor giving a notice about a receivable signal.

The term “single-carrier scheme and OFDM scheme related receptioncapability notification symbol 9401” is used, but the term is notlimited thereto, and another term may be used. For example, the term“symbol indicating the reception capability of the (third) terminal #p”may be used. In addition, the “single-carrier scheme and OFDM schemerelated reception capability notification symbol 9401” may includeinformation other than information for giving a notice about areceivable signal.

As in the present embodiment, the terminal #p forms and transmits areception capability notification symbol, and the base station receivesthe reception capability notification symbol, generates a modulatedsignal by considering the effectiveness of the value thereof, andtransmits the modulated signal. Accordingly, the terminal #p is able toreceive the modulated signal that can be demodulated, and is thus ableto appropriately obtain data and improve the data reception quality. Inaddition, the terminal #p generates data of each bit (each field) of thereception capability notification symbol while determining theeffectiveness of the bit (the field), and is thus able to reliablytransmit the reception capability notification symbol to the basestation and obtain an effect of improving the communication quality.

Twenty-first Embodiment

In the present embodiment, a supplemental description for the thirdembodiment, the fifth embodiment, and the fifteenth embodiment will begiven.

As illustrated in FIGS. 29 and 30 , the terminal #p transmits the data2901 about “support/not support reception for multiple streams” as apart of the reception capability notification symbol to the base stationor AP as a communication partner.

In the third embodiment, the fifth embodiment, the fifteenth embodiment,and so forth, the term “data 2901 about support/not support receptionfor multiple streams” is used, but the term is not limited thereto, andany reception capability notification symbol can be similarly used aslong as “support/not support reception for multiple streams” can beidentified. Hereinafter, an example thereof will be described.

For example, the following modulation and coding schemes (MCSs) areconsidered.

MCS #1:

An error-correcting coding scheme #A, a modulation scheme QPSK, andsingle-stream transmission are used to transmit data symbols.Accordingly, a transmission speed of 10 Mbps (bps: bits per second) canbe realized.

MCS #2:

The error-correcting coding scheme #A, a modulation scheme 16QAM, andsingle-stream transmission are used to transmit data symbols.Accordingly, a transmission speed of 20 Mbps can be realized.

MCS #3:

An error-correcting coding scheme #B, the modulation scheme QPSK, andsingle-stream transmission are used to transmit data symbols.Accordingly, a transmission speed of 15 Mbps can be realized.

MCS #4:

The error-correcting coding scheme #B, the modulation scheme 16QAM, andsingle-stream transmission are used to transmit data symbols.Accordingly, a transmission speed of 30 Mbps can be realized.

MCS #5:

The error-correcting coding scheme #A, the modulation scheme QPSK, andmulti-stream transmission with multiple antennas are used to transmitdata symbols. Accordingly, a transmission speed of 20 Mbps (bps: bitsper second) can be realized.

MCS #6:

The error-correcting coding scheme #A, the modulation scheme 16QAM, andmulti-stream transmission with multiple antennas are used to transmitdata symbols. Accordingly, a transmission speed of 40 Mbps can berealized.

MCS #7:

The error-correcting coding scheme #B, the modulation scheme QPSK, andmulti-stream transmission with multiple antennas are used to transmitdata symbols. Accordingly, a transmission speed of 30 Mbps can berealized.

MCS #8:

The error-correcting coding scheme #B, the modulation scheme 16QAM, andmulti-stream transmission with multiple antennas are used to transmitdata symbols. Accordingly, a transmission speed of 60 Mbps can berealized.

At this time, it is assumed that the terminal #p transmits the receptioncapability notification symbol to notify the base station or AP as acommunication partner that “demodulation of “MCS #1, MCS #2, MCS #3, andMCS #4” can be performed“, or “demodulation of “MCS #1, MCS #2, MCS #3,MCS #4, MCS #5, MCS #6, MCS #7, and MCS #8” can be performed“. In thiscase, the communication partner is notified that demodulation ofsingle-stream transmission can be performed, or the communicationpartner is notified that “demodulation of single-stream transmission canbe performed” and “demodulation of multi-stream transmission withmultiple antennas can be performed”, and a function similar tonotification of the data 2901 about “support/not support reception formultiple streams” is realized.

However, in a case where the terminal #p uses the reception capabilitynotification symbol to notify the base station or AP as a communicationpartner of an MCS set in which the terminal #p supports thedemodulation, there is an advantage that the terminal #p is able tonotify the base station or AP as a communication partner of the detailsof the MCS set in which the terminal #p supports the demodulation.

In addition, FIG. 27 illustrates an example of communication between thebase station or AP and the terminal #p, but the style of communicationbetween the base station or AP and the terminal #p is not limited tothat in FIG. 27 . For example, it is important in the present disclosurethat the terminal #p transmits the reception capability notificationsymbol to a communication partner (for example, the base station or AP)in the third embodiment, the fifth embodiment, the fifteenth embodiment,the twentieth embodiment, and so forth. Accordingly, the effectsdescribed in the individual embodiments can be obtained. At this time,the communication between the terminal #p and the communication partnerof the terminal #p before the terminal #p transmits the receptioncapability notification symbol to the communication partner is notlimited to that in FIG. 27 .

Twenty-Second Embodiment

In the present embodiment, a description will be given of another methodfor carrying out the operation of the terminal #p that has beendescribed in the third embodiment, the fifth embodiment, the fifteenthembodiment, and so forth.

The base station or AP has the configuration illustrated in FIG. 22 ,for example, and receives a signal transmitted by the terminal #p. Theconfiguration in FIG. 22 has already been described, and thus thedescription thereof is omitted.

FIG. 34 is an example of the configuration of the terminal #p, which isa communication partner of the base station or AP. The description hasalready been given, and thus the description is omitted.

FIG. 27 illustrates an example of communication between the base stationor AP and the terminal #p. The details thereof have been described inthe third embodiment, the fifth embodiment, the fifteenth embodiment,and so forth, and thus the description thereof is omitted.

FIG. 80 illustrates a specific example configuration of the receptioncapability notification symbol 2702 transmitted by the terminal #pillustrated in FIG. 27 .

Before describing FIG. 80 , a description will be given of theconfiguration of the terminal #p that exists as the terminal #p thatcommunicates with the base station or AP.

In the present embodiment, it is assumed that the following types ofterminals #p may exist.

Terminal Type #1:

It is possible to demodulate a modulated signal of the single-carrierscheme and single-stream transmission.

Terminal Type #2:

It is possible to demodulate a modulated signal of the single-carrierscheme and single-stream transmission. Additionally, it is possible toreceive and demodulate multiple modulated signals of the single-carrierscheme transmitted by a communication partner by using multipleantennas.

Terminal Type #3:

It is possible to demodulate a modulated signal of the single-carrierscheme and single-stream transmission. Furthermore, it is possible todemodulate a modulated signal of the OFDM scheme and single-streamtransmission.

Terminal Type #4:

It is possible to demodulate a modulated signal of the single-carrierscheme and single-stream transmission. Additionally, it is possible toreceive and demodulate multiple modulated signals of the single-carrierscheme transmitted by a communication partner by using multipleantennas. Furthermore, it is possible to demodulate a modulated signalof the OFDM scheme and single-stream transmission. Additionally, it ispossible to receive and demodulate multiple modulated signals of theOFDM scheme transmitted by a communication partner by using multipleantennas.

Terminal Type #5:

It is possible to demodulate a modulated signal of the OFDM scheme andsingle-stream transmission.

Terminal Type #6:

It is possible to demodulate a modulated signal of the OFDM scheme andsingle-stream transmission. Additionally, it is possible to receive anddemodulate multiple modulated signals of the OFDM scheme transmitted bya communication partner by using multiple antennas.

In the present embodiment, for example, it is assumed that the terminals#p of the terminal type #1 to the terminal type #6 may communicate withthe base station or AP. Note that the base station or AP may communicatewith the terminal #p of a type different from the terminal type #1 tothe terminal type #6.

In view of the above, the reception capability notification symbol inFIG. 80 will be described.

FIG. 80 illustrates an example of a specific configuration of thereception capability notification symbol 2702 transmitted by theterminal #p illustrated in FIG. 27 .

As illustrated in FIG. 80 , the “single-carrier scheme and OFDM schemerelated reception capability notification symbol 9401”, the“single-carrier scheme related reception capability notification symbol9402”, and the “OFDM scheme related reception capability notificationsymbol 9403” constitute a reception capability notification symbol. Areception capability notification symbol other than those illustrated inFIG. 80 may be included.

It is assumed that the “single-carrier scheme and OFDM scheme relatedreception capability notification symbol 9401” includes data fornotifying a communication partner (in this case, for example, the basestation or AP) of the reception capability for both a modulated signalof the single-carrier scheme and a modulated signal of the OFDM scheme.

Also, it is assumed that the “single-carrier scheme related receptioncapability notification symbol 9402” includes data for notifying acommunication partner (in this case, for example, the base station orAP) of the reception capability for a modulated signal of thesingle-carrier scheme.

It is assumed that the “OFDM scheme related reception capabilitynotification symbol 9403” includes data for notifying a communicationpartner (in this case, for example, the base station or AP) of thereception capability for a modulated signal of the OFDM scheme.

FIG. 81 illustrates an example of the configuration of the“single-carrier scheme and OFDM scheme related reception capabilitynotification symbol 9401” illustrated in FIG. 80 .

It is assumed that the “single-carrier scheme and OFDM scheme relatedreception capability notification symbol 9401” illustrated in FIG. 80includes the data 9501 about “support of SISO or MIMO (MISO)”, the data9502 about “supported error-correcting coding schemes”, and the data9503 about “support status of single-carrier scheme and OFDM scheme” inFIG. 81 .

When the data 9501 about “support of SISO or MIMO (MISO)” is g0 and g1,the terminal #p performs the following operation, for example.

For example, it is assumed that, in a case where the communicationpartner of the terminal #p transmits a modulated signal of a singlestream and the terminal #p is able to demodulate the modulated signal,the terminal #p sets g0=1 and g1=0, and the terminal #p transmits areception capability notification symbol including g0 and g1.

It is assumed that, in a case where the communication partner of theterminal #p transmits multiple different modulated signals by usingmultiple antennas and the terminal #p is able to demodulate themodulated signals, the terminal #p sets g0=0 and g1=1, and the terminal#p transmits a reception capability notification symbol including g0 andg1.

It is assumed that, in a case where the communication partner of theterminal #p transmits a modulated signal of a single stream and theterminal #p is able to demodulate the modulated signal, and in a casewhere the communication partner of the terminal #p transmits multipledifferent modulated signals by using multiple antennas and the terminal#p is able to demodulate the modulated signals, the terminal #p setsg0=1 and g1=1, and the terminal #p transmits a reception capabilitynotification symbol including g0 and g1.

When the data 9502 about “supported error-correcting coding schemes” isg2, the terminal #p performs the following operation, for example.

For example, it is assumed that, in a case where the terminal #p is ableto perform error-correcting decoding on data of a first error-correctingcoding scheme, the terminal #p sets g2=0, and the terminal #p transmitsa reception capability notification symbol including g2.

It is assumed that, in a case where the terminal #p is able to performerror-correcting decoding on data of the first error-correcting codingscheme and is able to perform error-correcting decoding on data of asecond error-correcting coding scheme, the terminal #p sets g2=1, andthe terminal #p transmits a reception capability notification symbolincluding g2.

As another case, it is assumed that each terminal #p is able to performerror-correcting decoding on data of the first error-correcting codingscheme. Furthermore, in a case where the terminal #p is able to performerror-correcting decoding on data of the second error-correcting codingscheme, the terminal #p sets g2=1, and in a case where the terminal #pdoes not support error-correcting decoding on data of the seconderror-correcting coding scheme, the terminal #p sets g2=0. It is assumedthat the terminal #p transmits a reception capability notificationsymbol including g2.

It is assumed that the first error-correcting coding scheme and thesecond error-correcting coding scheme are different schemes. Forexample, it is assumed that the block length (code length) of the firsterror-correcting coding scheme is A bits (A is an integer equal to orgreater than 2), the block length (code length) of the seconderror-correcting coding scheme is B bits (B is an integer equal to orgreater than 2), and A≠B holds. However, an example of the differentschemes is not limited thereto, and the error-correcting code used inthe first error-correcting coding scheme and the error-correcting codeused in the second error-correcting coding scheme may be different fromeach other.

When the data 9503 about “support status of single-carrier scheme andOFDM scheme” is g3 and g4, the terminal #p performs the followingoperation, for example.

For example, it is assumed that, in a case where the terminal #p is ableto demodulate a modulated signal of the single-carrier scheme, theterminal #p sets g3=1 and g4=0 (in this case, the terminal #p does notsupport demodulation of a modulated signal of OFDM), and the terminal #ptransmits a reception capability notification symbol including g3 andg4.

It is assumed that, in a case where the terminal #p is able todemodulate a modulated signal of the OFDM scheme, the terminal #p setsg3=0 and g4=1 (in this case, the terminal #p does not supportdemodulation of a modulated signal of the single-carrier scheme), andthe terminal #p transmits a reception capability notification symbolincluding g3 and g4.

It is assumed that, in a case where the terminal #p is able todemodulate a modulated signal of the single-carrier scheme and is ableto demodulate a modulated signal of the OFDM scheme, the terminal #psets g3=1 and g4=1, and the terminal #p transmits a reception capabilitynotification symbol including g3 and g4.

FIG. 82 illustrates an example of the configuration of the“single-carrier scheme related reception capability notification symbol9402” illustrated in FIG. 80 .

It is assumed that the “single-carrier scheme related receptioncapability notification symbol 9402” illustrated in FIG. 80 includes thedata 9601 about “schemes supported by single-carrier scheme” in FIG. 82.

When the data 9601 about “schemes supported by single-carrier scheme” ish0 and h1, the terminal #p performs the following operation, forexample.

For example, it is assumed that, in a case where the communicationpartner of the terminal #p transmits a modulated signal by performingchannel bonding and the terminal #p is able to demodulate the modulatedsignal, the terminal #p sets h0=1, whereas in a case where the terminal#p does not support demodulation of the modulated signal, the terminal#p sets h0=0, and the terminal #p transmits a reception capabilitynotification symbol including h0.

It is assumed that, in a case where the communication partner of theterminal #p transmits a modulated signal by performing channelaggregation and the terminal #p is able to demodulate the modulatedsignal, the terminal #p sets h1=1, whereas in a case where the terminal#p does not support demodulation of the modulated signal, the terminal#p sets h1=0, and the terminal #p transmits a reception capabilitynotification symbol including h1.

In a case where the terminal #p sets g3 to 0 and g4 to 1, since theterminal #p does not support demodulation of a modulated signal of thesingle-carrier scheme, the bit (field) of h0 is an invalid bit (field),and also the bit (field) of h1 is an invalid bit (field).

In a case where the terminal #p sets g3 to 0 and g4 to 1, the above h0and h1 may be regarded as a reserved (maintained for the future) bit(field) according to the prescription given in advance, or the terminal#p may determine the above h0 and h1 to be an invalid bit (field) (maydetermine the above h0 or h1 to be an invalid bit (field)), or the basestation or AP may obtain the above h0 and h1 and determine h0 and h1 tobe an invalid bit (field) (may determine the above h0 or h1 to be aninvalid bit (field)).

According to the description given above, there is a case where theterminal #p sets g3 to 0 and g4 to 1, that is, a case where the terminal#p does not support demodulation of a modulated signal of thesingle-carrier scheme, but an embodiment is possible in which eachterminal #p “supports the demodulation of the single-carrier scheme”. Inthis case, the bit (field) of g3 described above is not necessary.

FIG. 85 illustrates an example of the configuration of the “OFDM schemerelated reception capability notification symbol 9403” illustrated inFIG. 80 .

It is assumed that the “OFDM scheme related reception capabilitynotification symbol 9403” illustrated in FIG. 80 includes the data 9701about “schemes supported by OFDM scheme” in FIG. 85 .

In addition, it is assumed that the data 9701 about “schemes supportedby OFDM scheme” includes the data 5301 about “supported precodingmethods” illustrated in FIG. 71 and so forth. The data 5301 about“supported precoding methods” has been described in the fifteenthembodiment and so forth, and thus the detailed description thereof isomitted. In the fifteenth embodiment, a description is given using theprecoding method #A and the precoding method #B, but the precodingmatrix in the precoding method #A is not limited to that using theprecoding matrix described in the fifteenth embodiment, and a precodingmatrix described in this specification may be applied, for example.Also, the precoding matrix in the precoding method #B is not limited tothat using the precoding matrix described in the fifteenth embodiment,and a precoding matrix described in this specification may be applied,for example (it is assumed that the precoding method #A and theprecoding method #B are different from each other, and, for example, theprecoding matrix in the precoding method #A and the precoding matrix inthe precoding method #B are different from each other).

The precoding method #A may be a “method of not performing precodingprocessing”, and the precoding method #B may be a “method of notperforming precoding processing”.

When the data 5301 about “supported precoding methods” is m0, theterminal #p performs the following operation, for example.

For example, assume a case where the communication partner of theterminal #p generates multiple modulated signals by performing precodingprocessing corresponding to the precoding method #A and transmits thegenerated multiple modulated signals by using multiple antennas. In thiscase, it is assumed that, in a case where the terminal #p is able todemodulate the modulated signals, the terminal #p sets m0=0, and theterminal #p transmits a reception capability notification symbolincluding m0.

Also, assume a case where the communication partner of the terminal #pgenerates multiple modulated signals by performing precoding processingcorresponding to the precoding method #B and transmits the generatedmultiple modulated signals by using multiple antennas. In this case, itis assumed that, in a case where the terminal #p is able to demodulatethe modulated signals, the terminal #p sets m0=1, and the terminal #ptransmits a reception capability notification symbol including m0.

In a case where the terminal #p sets g3 to 1 and g4 to 0, since theterminal #p does not support demodulation of a modulated signal of theOFDM scheme, the bit (field) of m0 is an invalid bit (field).

In a case where the terminal #p sets g3 to 1 and g4 to 0, the above m0may be regarded as a reserved (maintained for the future) bit (field)according to the prescription given in advance, or the terminal #p maydetermine the above m0 to be an invalid bit (field), or the base stationor AP may obtain the above m0 and determine m0 to be an invalid bit(field).

In the description given above, an embodiment is possible in which eachterminal #p “supports the demodulation of the single-carrier scheme”. Inthis case, the bit (field) of g3 described above is not necessary.

The base station that has received the reception capability notificationsymbol transmitted by the terminal #p described above generates andtransmits a modulated signal on the basis of the reception capabilitynotification symbol, and accordingly the terminal #p is able to receivea transmission signal that can be demodulated. A specific example of theoperation of the base station has been described in embodiments, such asthe third embodiment, the fifth embodiment, and the fifteenthembodiment.

An example of the precoding method #A and the precoding method #B willbe described. As an example, the case of transmitting two streams isconsidered. A first mapped signal and a second mapped signal forgenerating the two streams are represented by s1(i) and s2(i),respectively.

At this time, it is assumed that the precoding method #A is a scheme ofnot performing precoding (or precoding (weight combining) usingExpression (33) or Expression (34)).

Also, for example, it is assumed that the precoding method #B is thefollowing precoding method.

When the modulation scheme for s1(i) is BPSK or π/2 shift BPSK and themodulation scheme for s2(i) is BPSK or π/2 shift BPSK, it is assumedthat a precoding matrix F is expressed by the following Expression (71).

$\begin{matrix}{F = \begin{pmatrix}a_{b} & b_{b} \\c_{b} & d_{b}\end{pmatrix}} & {{Expression}(71)}\end{matrix}$

It is assumed that a_(b), b_(b), c_(b), and d_(b) are expressed bycomplex numbers (also may be real numbers). It is assumed that a_(b) isnot zero, b_(b) is not zero, c_(b) is not zero, and d_(b) is not zero.

When the modulation scheme for s1(i) is QPSK or π/2 shift QPSK and themodulation scheme for s2(i) is QPSK or π/2 shift QPSK, it is assumedthat a precoding matrix F is expressed by the following Expression (72).

$\begin{matrix}{F = \begin{pmatrix}a_{q} & b_{q} \\c_{q} & d_{q}\end{pmatrix}} & {{Expression}(72)}\end{matrix}$

It is assumed that a_(q), b_(q), c_(q), and d_(q) are expressed bycomplex numbers (also may be real numbers). It is assumed that a_(q) isnot zero, b_(q) is not zero, c_(q) is not zero, and d_(q) is not zero.

When the modulation scheme for s1(i) is 16QAM or π/2 shift 16QAM and themodulation scheme for s2(i) is 16QAM or π/2 shift 16QAM, it is assumedthat a precoding matrix F is expressed by the following Expression (73).

$\begin{matrix}{F = \begin{pmatrix}a_{16} & b_{16} \\c_{16} & d_{16}\end{pmatrix}} & {{Expression}(73)}\end{matrix}$

It is assumed that a₁₆, b₁₆, c₁₆, and d₁₆ are expressed by complexnumbers (also may be real numbers). It is assumed that a₁₆ is not zero,b₁₆ is not zero, c₁₆ is not zero, and d₁₆ is not zero.

When the modulation scheme for s1(i) is 64QAM or π/2 shift 64QAM and themodulation scheme for s2(i) is 64QAM or π/2 shift 64QAM, it is assumedthat a precoding matrix F is expressed by the following Expression (74).

$\begin{matrix}{F = \begin{pmatrix}a_{64} & b_{64} \\c_{64} & d_{64}\end{pmatrix}} & {{Expression}(74)}\end{matrix}$

It is assumed that a₆₄, b₆₄, c₆₄, and d₆₄ are expressed by complexnumbers (also may be real numbers). It is assumed that a₆₄ is not zero,b₆₄ is not zero, c₆₄ is not zero, and d₆₄ is not zero.

In the precoding method #A and the precoding method #B, the set of themodulation scheme for s1(i) and the modulation scheme for s2(i) is notlimited to the above-described sets. The modulation scheme for s1(i) andthe modulation scheme for s2(i) may be different, for example, “themodulation scheme for s1(i) is BPSK or π/2 shift BPSK and the modulationscheme for s2(i) is QPSK or π/2 shift QPSK” or “the modulation schemefor s1(i) is QPSK or π/2 shift QPSK and the modulation scheme for s2(i)is 16QAM or π/2 shift 16QAM”.

Next, the configuration in FIG. 86 will be described as theconfiguration of the “OFDM scheme related reception capabilitynotification symbol 9403” illustrated in FIG. 80 , different from FIG.85 .

It is assumed that the “OFDM scheme related reception capabilitynotification symbol 9403” illustrated in FIG. 80 includes the data 9701about “schemes supported by OFDM scheme” in FIG. 86 .

In addition, it is assumed that the data 9701 about “schemes supportedby OFDM scheme” includes the data 5301 about “supported precodingmethods” illustrated in FIG. 71 and so forth. The data 5301 about“supported precoding methods” has been described in the fifteenthembodiment and so forth, and thus the detailed description thereof isomitted. In the fifteenth embodiment, a description is given using theprecoding method #A and the precoding method #B, but the precodingmatrix in the precoding method #A is not limited to that using theprecoding matrix described in the fifteenth embodiment, and a precodingmatrix described in this specification may be applied, for example.Also, the precoding matrix in the precoding method #B is not limited tothat using the precoding matrix described in the fifteenth embodiment,and a precoding matrix described in this specification may be applied,for example (it is assumed that the precoding method #A and theprecoding method #B are different from each other, and, for example, theprecoding matrix in the precoding method #A and the precoding matrix inthe precoding method #B are different from each other).

The precoding method #A may be a “method of not performing precodingprocessing”, and the precoding method #B may be a “method of notperforming precoding processing”.

Furthermore, it is assumed that the data 9701 about “schemes supportedby OFDM scheme” includes the data 2801 about “support/not supportdemodulation of modulated signal with phase change” illustrated in FIGS.28, 30, 71 , and so forth. The data 2801 about “support/not supportdemodulation of modulated signal with phase change” has been describedin the third embodiment, the fifth embodiment, the fifteenth embodiment,and so forth, and thus the detailed description is omitted.

When the data 5301 about “supported precoding methods” is m0, theterminal #p performs the following operation, for example.

For example, assume a case where the communication partner of theterminal #p generates multiple modulated signals by performing precodingprocessing corresponding to the precoding method #A and transmits thegenerated multiple modulated signals by using multiple antennas. In thiscase, it is assumed that, in a case where the terminal #p is able todemodulate the modulated signals, the terminal #p sets m0=0, and theterminal #p transmits a reception capability notification symbolincluding m0.

Also, assume a case where the communication partner of the terminal #pgenerates multiple modulated signals by performing precoding processingcorresponding to the precoding method #B and transmits the generatedmultiple modulated signals by using multiple antennas. In this case, itis assumed that, in a case where the terminal #p is able to demodulatethe modulated signals, the terminal #p sets m0=1, and the terminal #ptransmits a reception capability notification symbol including m0.

In a case where the terminal #p sets g3 to 1 and g4 to 0, since theterminal #p does not support demodulation of a modulated signal of theOFDM scheme, the bit (field) of m0 is an invalid bit (field).

In a case where the terminal #p sets g3 to 1 and g4 to 0, the above m0may be regarded as a reserved (maintained for the future) bit (field)according to the prescription given in advance, or the terminal #p maydetermine the above m0 to be an invalid bit (field), or the base stationor AP may obtain the above m0 and determine m0 to be an invalid bit(field).

In the description given above, an embodiment is possible in which eachterminal #p “supports the demodulation of the single-carrier scheme”. Inthis case, the bit (field) of g3 described above is not necessary.

When the data 2801 about “support/not support demodulation of modulatedsignal with phase change” is m1, the terminal #p performs the followingoperation, for example.

For example, assume a case where the communication partner of theterminal #p generates multiple modulated signals by performing phasechange processing and transmits the generated multiple modulated signalsby using multiple antennas. In this case, it is assumed that, in a casewhere the terminal #p is able to demodulate the modulated signals, theterminal #p sets m1=1, whereas in a case where the terminal #p does notsupport demodulation of the modulated signals, the terminal #p setsm1=0, and the terminal #p transmits a reception capability notificationsymbol including m1.

In a case where the terminal #p sets g3 to 1 and g4 to 0, since theterminal #p does not support demodulation of a modulated signal of theOFDM scheme, the bit (field) of m1 is an invalid bit (field).

In a case where the terminal #p sets g3 to 1 and g4 to 0, the above m1may be regarded as a reserved (maintained for the future) bit (field)according to the prescription given in advance, or the terminal #p maydetermine the above m1 to be an invalid bit (field), or the base stationor AP may obtain the above m1 and determine m1 to be an invalid bit(field).

In the description given above, an embodiment is possible in which eachterminal #p “supports the demodulation of the single-carrier scheme”. Inthis case, the bit (field) of g3 described above is not necessary.

In the example in FIG. 86 , a supported precoding method in the data5301 about “supported precoding methods” may be a precoding method whenperform/not perform phase change can be set in the data 2801 about“support/not support demodulation of modulated signal with phasechange”. Alternatively, a supported precoding method in the data 5301about “supported precoding methods” does not depend on the setting ofperform/not perform phase change, and the precoding method may be set.

With the embodiment being carried out in the above-described manner, thefollowing example characteristics can be obtained.

Characteristic #1

“A first reception apparatus, where

-   -   the reception apparatus generates control information indicating        a signal receivable by the reception apparatus, the control        information including a first region, a second region, a third        region, and a fourth region,    -   the first region is a region storing information indicating        whether or not it is possible to receive a signal for        transmitting data generated by using a single-carrier scheme and        information indicating whether or not it is possible to receive        a signal generated by using a multi-carrier scheme,    -   the second region is a region storing information indicating        whether or not it is possible to receive a signal generated by        using any one of one or more schemes usable in both or either of        a case of generating a signal by using the single-carrier scheme        and a case of generating a signal by using the multi-carrier        scheme,    -   the third region is    -   in a case of storing, in the first region, information        indicating that it is possible to receive a signal for        transmitting data generated by using the single-carrier scheme,        a region storing information indicating whether or not it is        possible to receive a signal generated by using any one of one        or more schemes usable in a case of generating a signal by using        the single-carrier scheme, and    -   in a case of storing, in the first region, information        indicating that it is impossible to receive a signal for        transmitting data generated by using the single-carrier scheme,        an invalid or reserved region, the fourth region is    -   in a case of storing, in the first region, information        indicating that it is possible to receive a signal for        transmitting data generated by using the multi-carrier scheme, a        region storing information indicating whether or not it is        possible to receive a signal generated by using any one of one        or more schemes usable in a case of generating a signal by using        the multi-carrier scheme, and    -   in a case of storing, in the first region, information        indicating that it is impossible to receive a signal for        transmitting data generated by using the multi-carrier scheme,        an invalid or reserved region, and    -   the reception apparatus generates a control signal from the        control information and transmits the control signal to a        transmission apparatus.”

“The above-described first reception apparatus, where

-   -   the second region includes a fifth region storing information        indicating whether or not it is possible to receive a signal        generated by using the Multiple-Input Multiple-Output (MIMO)        scheme,    -   the second region or the fourth region includes a sixth region        storing information indicating whether or not it is possible to        receive a signal generated by using a phase change scheme for        performing phase change while regularly switching a phase change        value with respect to at least any one of signals of multiple        transmission systems for transmitting data, and    -   the reception apparatus sets a bit located in the sixth region        to a predetermined value in a case of storing, in the first        region, information indicating that it is impossible to receive        a signal for transmitting data generated by using the        multi-carrier scheme, or in a case of storing, in the first        region, information indicating that it is possible to receive a        signal for transmitting data generated by using the        multi-carrier scheme and storing, in the fifth region,        information indicating that it is impossible to receive a signal        of the MIMO scheme.”

“A first transmission apparatus that

-   -   receives the control signal from the above-described first        reception apparatus,    -   demodulates the received control signal to obtain the control        signal, and    -   decides, on the basis of the control signal, a scheme to be used        to generate a signal to be transmitted to the reception        apparatus.”

“The above-described first transmission apparatus, where

-   -   the second region includes a fifth region storing information        indicating whether or not it is possible to receive a signal        generated by using the Multiple-Input Multiple-Output (MIMO)        scheme,    -   the second region or the fourth region includes a sixth region        storing information indicating whether or not it is possible to        receive a signal generated by using a phase change scheme for        performing phase change while regularly switching a phase change        value with respect to at least any one of signals of multiple        transmission systems for transmitting data, and    -   the transmission apparatus decides a scheme to be used to        generate a signal to be transmitted to the reception apparatus        without using a value of a bit located in the sixth region in a        case where the first region includes information indicating that        it is impossible to receive a signal for transmitting data        generated by using the multi-carrier scheme, or in a case where        the first region includes information indicating that it is        possible to receive a signal for transmitting data generated by        using the multi-carrier scheme and the fifth region includes        information indicating that it is impossible to receive a signal        of the MIMO scheme.”

Characteristic #2

“A second reception apparatus, where

-   -   the reception apparatus generates control information indicating        a signal receivable by the reception apparatus, the control        information including a first region, a second region, a third        region, and a fourth region,    -   the first region is a region storing information indicating        whether or not it is possible to receive a signal generated by        using a multi-carrier scheme,    -   the second region is a region storing information indicating        whether or not it is possible to receive a signal generated by        using any one of one or more schemes usable in both or either of        a case of generating a signal by using a single-carrier scheme        and a case of generating a signal by using the multi-carrier        scheme,    -   the third region is a region storing information indicating        whether or not it is possible to receive a signal generated by        using any one of one or more schemes usable in a case of        generating a signal by using the single-carrier scheme,    -   the fourth region is    -   in a case of storing, in the first region, information        indicating that it is possible to receive a signal for        transmitting data generated by using the multi-carrier scheme, a        region storing information indicating whether or not it is        possible to receive a signal generated by using any one of one        or more schemes usable in a case of generating a signal by using        the multi-carrier scheme, and    -   in a case of storing, in the first region, information        indicating that it is impossible to receive a signal for        transmitting data generated by using the multi-carrier scheme,        an invalid or reserved region, and    -   the reception apparatus generates a control signal from the        control information and transmits the control signal to a        transmission apparatus.”

“The above-described second reception apparatus, where

-   -   the second region includes a fifth region storing information        indicating whether or not it is possible to receive a signal        generated by using the Multiple-Input Multiple-Output (MIMO)        scheme,    -   the second region or the fourth region includes a sixth region        storing information indicating whether or not it is possible to        receive a signal generated by using a phase change scheme for        performing phase change while regularly switching a phase change        value with respect to at least any one of signals of multiple        transmission systems for transmitting data, and    -   the reception apparatus sets a bit located in the sixth region        to a predetermined value in a case of storing, in the first        region, information indicating that it is impossible to receive        a signal for transmitting data generated by using the        multi-carrier scheme, or in a case of storing, in the first        region, information indicating that it is possible to receive a        signal for transmitting data generated by using the        multi-carrier scheme and storing, in the fifth region,        information indicating that it is impossible to receive a signal        of the MIMO scheme.”

“A second transmission apparatus that

-   -   receives the control signal from the above-described second        reception apparatus,    -   demodulates the received control signal to obtain the control        signal, and    -   decides, on the basis of the control signal, a scheme to be used        to generate a signal to be transmitted to the reception        apparatus.”

“The above-described second transmission apparatus, where

-   -   the second region includes a fifth region storing information        indicating whether or not it is possible to receive a signal        generated by using the Multiple-Input Multiple-Output (MIMO)        scheme,    -   the second region or the fourth region includes a sixth region        storing information indicating whether or not it is possible to        receive a signal generated by using a phase change scheme for        performing phase change while regularly switching a phase change        value with respect to at least any one of signals of multiple        transmission systems for transmitting data, and    -   the transmission apparatus decides a scheme to be used to        generate a signal to be transmitted to the reception apparatus        without using a value of a bit located in the sixth region in a        case where the first region includes information indicating that        it is impossible to receive a signal for transmitting data        generated by using the multi-carrier scheme, or in a case where        the first region includes information indicating that it is        possible to receive a signal for transmitting data generated by        using the multi-carrier scheme and the fifth region includes        information indicating that it is impossible to receive a signal        of the MIMO scheme.”

In the present embodiment, the configuration in FIG. 80 has beendescribed as an example of the configuration of the reception capabilitynotification symbol 2702 in FIG. 27 , but the configuration is notlimited thereto, and a reception capability notification symboldifferent from that in FIG. 80 may exist. For example, the configurationin FIG. 84 may be used.

In FIG. 84 , the elements that operate similarly to those in FIG. 80 aredenoted by the same numerals, and the description thereof is omitted. InFIG. 84 , the other reception capability notification symbol 9801 isadded as a reception capability notification symbol.

The other reception capability notification symbol 9801 is, for example,a reception capability notification symbol that is not the“single-carrier scheme and OFDM scheme related reception capabilitynotification symbol 9401”, that is not the “single-carrier schemerelated reception capability notification symbol 9402”, and that is notthe “OFDM scheme related reception capability notification symbol 9403”.

Also with such a reception capability notification symbol, theabove-described embodiments can be carried out similarly.

In FIG. 80 , a description has been given of an example of the receptioncapability notification symbol in which the “single-carrier scheme andOFDM scheme related reception capability notification symbol 9401”, the“single-carrier scheme related reception capability notification symbol9402”, and the “OFDM scheme related reception capability notificationsymbol 9403” are arranged in this order, but the reception capabilitynotification symbol is not limited thereto. An example thereof will bedescribed below.

In FIG. 80 , it is assumed that bit r0, bit r1, bit r2, and bit r3 existas the “single-carrier scheme and OFDM scheme related receptioncapability notification symbol 9401”. Also, it is assumed that bit r4,bit r5, bit r6, and bit r7 exist as the “single-carrier scheme relatedreception capability notification symbol 9402”. Also, it is assumed thatbit r8, bit r9, bit r10, and bit r11 exist as the “OFDM scheme relatedreception capability notification symbol 9403”.

In the case of FIG. 80 , it is assumed that bit r1, bit r2, bit r3, bitr4, bit r5, bit r6, bit r7, bit r8, bit r9, bit r10, and bit r11 arearranged in order, and are located in this order with respect to aframe, for example.

As another method, a bit sequence in which the order of “bit r1, bit r2,bit r3, bit r4, bit r5, bit r6, bit r7, bit r8, bit r9, bit r10, and bitr11” is changed, for example, a bit sequence of “bit r7, bit r2, bit r4,bit r6, bit r1, bit r8, bit r9, bit r5, bit r10, bit r3, and bit r11”may be located in this order with respect to a frame. The order in thebit sequence is not limited to this example.

In addition, in FIG. 80 , it is assumed that field s0, field s1, fields2, and field s3 exist as the “single-carrier scheme and OFDM schemerelated reception capability notification symbol 9401”. Also, it isassumed that field s4, field s5, field s6, and field s7 exist as the“single-carrier scheme related reception capability notification symbol9402”. Also, it is assumed that field s8, field s9, field s10, and fields11 exist as the “OFDM scheme related reception capability notificationsymbol 9403”. It is assumed that a “field” is made up of one or morebits.

In the case of FIG. 80 , it is assumed that field s1, field s2, fields3, field s4, field s5, field s6, field s7, field s8, field s9, fields10, and field s11 are arranged in order, and are located in this orderwith respect to a frame, for example.

As another method, a field sequence in which the order of “field s1,field s2, field s3, field s4, field s5, field s6, field s7, field s8,field s9, field s10, and field s11” is changed, for example, a fieldsequence of “field s7, field s2, field s4, field s6, field s1, field s8,field s9, field s5, field s10, field s3, and field s11” may be locatedin this order with respect to a frame. The order in the field sequenceis not limited to this example.

In FIG. 84 , a description has been given of an example of the receptioncapability notification symbol in which the “single-carrier scheme andOFDM scheme related reception capability notification symbol 9401”, the“single-carrier scheme related reception capability notification symbol9402”, the “OFDM scheme related reception capability notification symbol9403”, and the “other reception capability notification symbol 9801” arearranged in this order, but the reception capability notification symbolis not limited thereto. An example thereof will be described below.

In FIG. 84 , it is assumed that bit r0, bit r1, bit r2, and bit r3 existas the “single-carrier scheme and OFDM scheme related receptioncapability notification symbol 9401”. Also, it is assumed that bit r4,bit r5, bit r6, and bit r7 exist as the “single-carrier scheme relatedreception capability notification symbol 9402”. Also, it is assumed thatbit r8, bit r9, bit r10, and bit r11 exist as the “OFDM scheme relatedreception capability notification symbol 9403”. Also, it is assumed thatbit r12, bit r13, bit r14, and bit r15 exist as the “other receptioncapability notification symbol 9801”.

In the case of FIG. 84 , it is assumed that bit r1, bit r2, bit r3, bitr4, bit r5, bit r6, bit r7, bit r8, bit r9, bit r10, bit r11, bit r12,bit r13, bit r14, and bit r15 are arranged in order, and are located inthis order with respect to a frame, for example.

As another method, a bit sequence in which the order of “bit r1, bit r2,bit r3, bit r4, bit r5, bit r6, bit r7, bit r8, bit r9, bit r10, bitr11, bit r12, bit r13, bit r14, and bit r15” is changed, for example, abit sequence of “bit r7, bit r2, bit r4, bit r6, bit r13, bit r1, bitr8, bit r12, bit r9, bit r5, bit r10, bit r3, bit r15, bit r11, and bitr14” may be located in this order with respect to a frame. The order inthe bit sequence is not limited to this example.

In addition, in FIG. 84 , it is assumed that field s0, field s1, fields2, and field s3 exist as the “single-carrier scheme and OFDM schemerelated reception capability notification symbol 9401”. Also, it isassumed that field s4, field s5, field s6, and field s7 exist as the“single-carrier scheme related reception capability notification symbol9402”. Also, it is assumed that field s8, field s9, field s10, and fields11 exist as the “OFDM scheme related reception capability notificationsymbol 9403”. Also, it is assumed that field s12, field s13, field s14,and field s15 exist as the “other reception capability notificationsymbol 9801”. It is assumed that a “field” is made up of one or morebits.

In the case of FIG. 84 , it is assumed that field s1, field s2, fields3, field s4, field s5, field s6, field s7, field s8, field s9, fields10, field s11, field s12, field s13, field s14, and field s15 arearranged in order, and are located in this order with respect to aframe, for example.

As another method, a field sequence in which the order of “field s1,field s2, field s3, field s4, field s5, field s6, field s7, field s8,field s9, field s10, field s11, field s12, field s13, field s14, andfield s15” is changed, for example, a field sequence of “field s7, fields2, field s4, field s6, field s13, field s1, field s8, field s12, fields9, field s5, field s10, field s3, field s15, field s11, and field s14”may be located in this order with respect to a frame. The order in thefield sequence is not limited to this example.

It is not always explicitly indicated that the information transmittedby the “single-carrier scheme related reception capability notificationsymbol” is information directed to the single-carrier scheme. Theinformation transmitted by the “single-carrier scheme related receptioncapability notification symbol” described in the present embodiment is,for example, information for giving a notice about a selectable schemein a case where the transmission apparatus transmits a signal in thesingle-carrier scheme. In another example, the information transmittedby the “single-carrier scheme related reception capability notificationsymbol” described in the present embodiment is, for example, informationthat is not used (ignored) to select a scheme to be used fortransmitting a signal in a case where the transmission apparatustransmits a signal in a scheme other than the single-carrier scheme,such as the OFDM scheme. In still another example, the informationtransmitted by the “single-carrier scheme related reception capabilitynotification symbol” described in the present embodiment is, forexample, information that is transmitted by using a region determined tobe an invalid region or reserved region by the transmission apparatus orthe reception apparatus in a case where the reception apparatus does notsupport the reception of a signal of the single-carrier scheme (notifiesthe transmission apparatus of non-support). In the above description,the term “single-carrier scheme related reception capabilitynotification symbol 9402” is used, but the term is not limited thereto,and another term may be used. For example, the term “symbol indicatingthe reception capability of the (first) terminal #p” may be used. Inaddition, the “single-carrier scheme related reception capabilitynotification symbol 9402” may include information other than informationfor giving a notice about a receivable signal.

Likewise, it is not always explicitly indicated that the informationtransmitted by the “OFDM scheme related reception capabilitynotification symbol” is information directed to the OFDM scheme. Theinformation transmitted by the “OFDM scheme related reception capabilitynotification symbol” described in the present embodiment is, forexample, information for giving a notice about a selectable scheme in acase where the transmission apparatus transmits a signal in the OFDMscheme. In another example, the information transmitted by the “OFDMscheme related reception capability notification symbol” described inthe present embodiment is, for example, information that is not used(ignored) to select a scheme to be used for transmitting a signal in acase where the transmission apparatus transmits a signal in a schemeother than the OFDM scheme, such as the single-carrier scheme. In stillanother example, the information transmitted by the “OFDM scheme relatedreception capability notification symbol” described in the presentembodiment is, for example, information that is transmitted by using aregion determined to be an invalid region or reserved region by thetransmission apparatus or the reception apparatus in a case where thereception apparatus does not support the reception of a signal of theOFDM scheme. In the above description, the term “OFDM scheme relatedreception capability notification symbol 9403” is used, but the term isnot limited thereto, and another term may be used. For example, the term“symbol indicating the reception capability of the (second) terminal #p”may be used. In addition, the “OFDM scheme related reception capabilitynotification symbol 9403” may include information other than informationfor giving a notice about a receivable signal.

The term “single-carrier scheme and OFDM scheme related receptioncapability notification symbol 9401” is used, but the term is notlimited thereto, and another term may be used. For example, the term“symbol indicating the reception capability of the (third) terminal #p”may be used. In addition, the “single-carrier scheme and OFDM schemerelated reception capability notification symbol 9401” may includeinformation other than information for giving a notice about areceivable signal.

As in the present embodiment, the terminal #p forms and transmits areception capability notification symbol, and the base station receivesthe reception capability notification symbol, generates a modulatedsignal by considering the effectiveness of the value thereof, andtransmits the modulated signal. Accordingly, the terminal #p is able toreceive the modulated signal that can be demodulated, and is thus ableto appropriately obtain data and improve the data reception quality. Inaddition, the terminal #p generates data of each bit (each field) of thereception capability notification symbol while determining theeffectiveness of the bit (the field), and is thus able to reliablytransmit the reception capability notification symbol to the basestation and improve the communication quality.

In the present embodiment, in a case where the base station or AP doesnot support precoding or does not support switching between theprecoding method #A and the precoding method #B (in this case, the basestation or AP supports either the precoding method #A or the precodingmethod #B), the base station or AP transmits a modulated signal withoutperforming precoding (or transmits a modulated signal by using either ofthe precoding methods) even if the terminal #p supports the precodingmethod.

In addition, in the present embodiment, a description has been given ofa case where there are two types of precoding methods: the precodingmethod #A and the precoding method #B, in a case where the terminal #p(and the base station or AP) supports precoding methods, but theembodiment is not limited thereto, and N types of precoding methods maybe supported (N is an integer equal to or greater than 2).

In the present embodiment, the twentieth embodiment, and so forth, in acase where the base station or AP does not support the transmission of amodulated signal that has been subjected to phase change, the basestation or AP transmits a modulated signal without performing phasechange even if the terminal #p supports the demodulation of a modulatedsignal whose phase has been changed.

Twenty-Third Embodiment

In the present embodiment, a description will be given of another methodfor carrying out the operation of the terminal #p described in the thirdembodiment, the fifth embodiment, and the fifteenth embodiment.

The present embodiment is an embodiment about a case where the basestation or AP performs transmission and reception by using the robustcommunication method described in the twelfth embodiment.

Regarding the transmission method in the robust communication methoddescribed in the twelfth embodiment, a description is given of, as anexample, the case where “processing of phase change and weight combiningis performed in FIGS. 3, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48 ,and so forth corresponding to the signal processor 206 in FIG. 2 ”, butphase change need not necessarily be performed by the phase changer305A, the phase changer 305B, the phase changer 309A, and the phasechanger 309B in FIGS. 3, 40, and 41 . At this time, an input signal isoutput as is without being subjected to phase change. For example, (inFIG. 3 ,) in a case where phase change is not performed by the phasechanger 305B, the signal 304B corresponds to the signal 306B. In a casewhere phase change is not performed by the phase changer 309B, thesignal 308B corresponds to the signal 310B. In a case where phase changeis not performed by the phase changer 305A, the signal 304A correspondsto the signal 306A. In a case where phase change is not performed by thephase changer 309A, the signal 308A corresponds to the signal 310A.

The phase changer 305A, the phase changer 305B, the phase changer 309A,and the phase changer 309B need not necessarily exist. For example, (inFIG. 3 ,) in a case where there is not the phase changer 305B, the input306B to the inserter 307B corresponds to the signal 304B. In a casewhere there is not the phase changer 309B, the signal 310B correspondsto the signal 308B. In a case where there is not the phase changer 305A,the input 306A to the inserter 307A corresponds to the signal 304A. In acase where there is not the phase changer 309A, the signal 310Acorresponds to the signal 308A.

The base station or AP has the configuration illustrated in FIG. 22 ,for example, and receives a signal transmitted by the terminal #p. Theconfiguration in FIG. 22 has already been described, and thus thedescription thereof is omitted.

FIG. 34 is an example of the configuration of the terminal #p, which isa communication partner of the base station or AP. The description hasalready been given, and thus the description is omitted.

FIG. 27 illustrates an example of communication between the base stationor AP and the terminal #p. The details thereof have been described inthe third embodiment, the fifth embodiment, the fifteenth embodiment,and so forth, and thus the description thereof is omitted.

FIG. 80 illustrates a specific example configuration of the receptioncapability notification symbol 2702 transmitted by the terminal #pillustrated in FIG. 27 .

Before describing FIG. 80 , a description will be given of theconfiguration of the terminal #p that exists as the terminal #p thatcommunicates with the base station or AP.

In the present embodiment, it is assumed that the following types ofterminals #p may exist.

Terminal Type #1:

It is possible to demodulate a modulated signal of the single-carrierscheme and single-stream transmission.

Terminal Type #2:

It is possible to demodulate a modulated signal of the single-carrierscheme and single-stream transmission. Additionally, it is possible toreceive and demodulate multiple modulated signals of the single-carrierscheme transmitted by a communication partner by using multipleantennas.

Terminal Type #3:

It is possible to demodulate a modulated signal of the single-carrierscheme and single-stream transmission. Furthermore, it is possible todemodulate a modulated signal of the OFDM scheme and single-streamtransmission.

Terminal Type #4:

It is possible to demodulate a modulated signal of the single-carrierscheme and single-stream transmission. Additionally, it is possible toreceive and demodulate multiple modulated signals of the single-carrierscheme transmitted by a communication partner by using multipleantennas. Furthermore, it is possible to demodulate a modulated signalof the OFDM scheme and single-stream transmission. Additionally, it ispossible to receive and demodulate multiple modulated signals of theOFDM scheme transmitted by a communication partner by using multipleantennas.

Terminal Type #5:

It is possible to demodulate a modulated signal of the OFDM scheme andsingle-stream transmission.

Terminal Type #6:

It is possible to demodulate a modulated signal of the OFDM scheme andsingle-stream transmission. Additionally, it is possible to receive anddemodulate multiple modulated signals of the OFDM scheme transmitted bya communication partner by using multiple antennas.

In the present embodiment, for example, it is assumed that the terminals#p of the terminal type #1 to the terminal type #6 may communicate withthe base station or AP. Note that the base station or AP may communicatewith the terminal #p of a type different from the terminal type #1 tothe terminal type #6.

In view of the above, the reception capability notification symbol inFIG. 80 will be described.

FIG. 80 illustrates an example of a specific configuration of thereception capability notification symbol 2702 transmitted by theterminal #p illustrated in FIG. 27 .

As illustrated in FIG. 80 , the “single-carrier scheme and OFDM schemerelated reception capability notification symbol 9401”, the“single-carrier scheme related reception capability notification symbol9402”, and the “OFDM scheme related reception capability notificationsymbol 9403” constitute a reception capability notification symbol. Areception capability notification symbol other than those illustrated inFIG. 80 may be included.

It is assumed that the “single-carrier scheme and OFDM scheme relatedreception capability notification symbol 9401” includes data fornotifying a communication partner (in this case, for example, the basestation or AP) of the reception capability for both a modulated signalof the single-carrier scheme and a modulated signal of the OFDM scheme.

Also, it is assumed that the “single-carrier scheme related receptioncapability notification symbol 9402” includes data for notifying acommunication partner (in this case, for example, the base station orAP) of the reception capability for a modulated signal of thesingle-carrier scheme.

It is assumed that the “OFDM scheme related reception capabilitynotification symbol 9403” includes data for notifying a communicationpartner (in this case, for example, the base station or AP) of thereception capability for a modulated signal of the OFDM scheme.

FIG. 81 illustrates an example of the configuration of the“single-carrier scheme and OFDM scheme related reception capabilitynotification symbol 9401” illustrated in FIG. 80 .

It is assumed that the “single-carrier scheme and OFDM scheme relatedreception capability notification symbol 9401” illustrated in FIG. 80includes the data 9501 about “support of SISO or MIMO (MISO)”, the data9502 about “supported error-correcting coding schemes”, and the data9503 about “support status of single-carrier scheme and OFDM scheme” inFIG. 81 .

When the data 9501 about “support of SISO or MIMO (MISO)” is g0 and g1,the terminal #p performs the following operation, for example.

For example, it is assumed that, in a case where the communicationpartner of the terminal #p transmits a modulated signal of a singlestream and the terminal #p is able to demodulate the modulated signal,the terminal #p sets g0=1 and g1=0, and the terminal #p transmits areception capability notification symbol including g0 and g1.

It is assumed that, in a case where the communication partner of theterminal #p transmits multiple different modulated signals by usingmultiple antennas and the terminal #p is able to demodulate themodulated signals, the terminal #p sets g0=0 and g1=1, and the terminal#p transmits a reception capability notification symbol including g0 andg1.

It is assumed that, in a case where the communication partner of theterminal #p transmits a modulated signal of a single stream and theterminal #p is able to demodulate the modulated signal, and in a casewhere the communication partner of the terminal #p transmits multipledifferent modulated signals by using multiple antennas and the terminal#p is able to demodulate the modulated signals, the terminal #p setsg0=1 and g1=1, and the terminal #p transmits a reception capabilitynotification symbol including g0 and g1.

When the data 9502 about “supported error-correcting coding schemes” isg2, the terminal #p performs the following operation, for example.

For example, it is assumed that, in a case where the terminal #p is ableto perform error-correcting decoding on data of a first error-correctingcoding scheme, the terminal #p sets g2=0, and the terminal #p transmitsa reception capability notification symbol including g2.

It is assumed that, in a case where the terminal #p is able to performerror-correcting decoding on data of the first error-correcting codingscheme and is able to perform error-correcting decoding on data of asecond error-correcting coding scheme, the terminal #p sets g2=1, andthe terminal #p transmits a reception capability notification symbolincluding g2.

As another case, it is assumed that each terminal #p is able to performerror-correcting decoding on data of the first error-correcting codingscheme. Furthermore, in a case where the terminal #p is able to performerror-correcting decoding on data of the second error-correcting codingscheme, the terminal #p sets g2=1, and in a case where the terminal #pdoes not support error-correcting decoding on data of the seconderror-correcting coding scheme, the terminal #p sets g2=0. It is assumedthat the terminal #p transmits a reception capability notificationsymbol including g2.

It is assumed that the first error-correcting coding scheme and thesecond error-correcting coding scheme are different schemes. Forexample, it is assumed that the block length (code length) of the firsterror-correcting coding scheme is A bits (A is an integer equal to orgreater than 2), the block length (code length) of the seconderror-correcting coding scheme is B bits (B is an integer equal to orgreater than 2), and A≠B holds. However, an example of the differentschemes is not limited thereto, and the error-correcting code used inthe first error-correcting coding scheme and the error-correcting codeused in the second error-correcting coding scheme may be different fromeach other.

When the data 9503 about “support status of single-carrier scheme andOFDM scheme” is g3 and g4, the terminal #p performs the followingoperation, for example.

For example, it is assumed that, in a case where the terminal #p is ableto demodulate a modulated signal of the single-carrier scheme, theterminal #p sets g3=1 and g4=0 (in this case, the terminal #p does notsupport demodulation of a modulated signal of OFDM), and the terminal #ptransmits a reception capability notification symbol including g3 andg4.

It is assumed that, in a case where the terminal #p is able todemodulate a modulated signal of the OFDM scheme, the terminal #p setsg3=0 and g4=1 (in this case, the terminal #p does not supportdemodulation of a modulated signal of the single-carrier scheme), andthe terminal #p transmits a reception capability notification symbolincluding g3 and g4.

It is assumed that, in a case where the terminal #p is able todemodulate a modulated signal of the single-carrier scheme and is ableto demodulate a modulated signal of the OFDM scheme, the terminal #psets g3=1 and g4=1, and the terminal #p transmits a reception capabilitynotification symbol including g3 and g4.

FIG. 82 illustrates an example of the configuration of the“single-carrier scheme related reception capability notification symbol9402” illustrated in FIG. 80 .

It is assumed that the “single-carrier scheme related receptioncapability notification symbol 9402” illustrated in FIG. 80 includes thedata 9601 about “schemes supported by single-carrier scheme” in FIG. 82.

When the data 9601 about “schemes supported by single-carrier scheme” ish0 and h1, the terminal #p performs the following operation, forexample.

For example, it is assumed that, in a case where the communicationpartner of the terminal #p transmits a modulated signal by performingchannel bonding and the terminal #p is able to demodulate the modulatedsignal, the terminal #p sets h0=1, whereas in a case where the terminal#p does not support demodulation of the modulated signal, the terminal#p sets h0=0, and the terminal #p transmits a reception capabilitynotification symbol including h0.

It is assumed that, in a case where the communication partner of theterminal #p transmits a modulated signal by performing channelaggregation and the terminal #p is able to demodulate the modulatedsignal, the terminal #p sets h1=1, whereas in a case where the terminal#p does not support demodulation of the modulated signal, the terminal#p sets h1=0, and the terminal #p transmits a reception capabilitynotification symbol including h1.

In a case where the terminal #p sets g3 to 0 and g4 to 1, since theterminal #p does not support demodulation of a modulated signal of thesingle-carrier scheme, the bit (field) of h0 is an invalid bit (field),and also the bit (field) of h1 is an invalid bit (field).

In a case where the terminal #p sets g3 to 0 and g4 to 1, the above h0and h1 may be regarded as a reserved (maintained for the future) bit(field) according to the prescription given in advance, or the terminal#p may determine the above h0 and h1 to be an invalid bit (field) (maydetermine the above h0 or h1 to be an invalid bit (field)), or the basestation or AP may obtain the above h0 and h1 and determine h0 and h1 tobe an invalid bit (field) (may determine the above h0 or h1 to be aninvalid bit (field)).

According to the description given above, there is a case where theterminal #p sets g3 to 0 and g4 to 1, that is, a case where the terminal#p does not support demodulation of a modulated signal of thesingle-carrier scheme, but an embodiment is possible in which eachterminal #p “supports the demodulation of the single-carrier scheme”. Inthis case, the bit (field) of g3 described above is not necessary.

FIG. 87 illustrates an example of the configuration of the “OFDM schemerelated reception capability notification symbol 9403” illustrated inFIG. 80 .

It is assumed that the “OFDM scheme related reception capabilitynotification symbol 9403” illustrated in FIG. 80 includes the data 9701about “schemes supported by OFDM scheme” in FIG. 87 .

In addition, it is assumed that the data 9701 about “schemes supportedby OFDM scheme” includes data 10101 about “support/not supportdemodulation of robust communication method (in twelfth embodiment)”.

In a case where the base station or AP as a communication partnertransmits a modulated signal in the communication method described inthe twelfth embodiment and the present embodiment and the terminal #p isable to demodulate the modulated signal, the terminal #p embeds dataindicating “support demodulation” in the data 10101 about “support/notsupport demodulation of robust communication method (in twelfthembodiment)” and transmits the data.

On the other hand, in a case where the base station or AP as acommunication partner transmits a modulated signal in the communicationmethod described in the twelfth embodiment and the present embodimentand the terminal #p does not support demodulation of the modulatedsignal, the terminal #p embeds data indicating “not supportdemodulation” in the data 10101 about “support/not support demodulationof robust communication method (in twelfth embodiment)” and transmitsthe data.

For example, when the data 10101 about “support/not support demodulationof robust communication method (in twelfth embodiment)” is n0, theterminal #p performs the following operation, for example.

It is assumes that, in a case where the terminal #p “does not supportdemodulation” described above, the terminal #p sets n0=0, and theterminal #p transmits a reception capability notification symbolincluding n0.

Also, it is assumed that, in a case where the terminal #p “supportsdemodulation (is able to perform demodulation)” described above, theterminal #p sets n0=1, and the terminal #p transmits a receptioncapability notification symbol including n0.

In a case where the terminal #p sets g3 to 1 and g4 to 0, since theterminal #p does not support demodulation of a modulated signal of theOFDM scheme, the bit (field) of n0 is an invalid bit (field).

In a case where the terminal #p sets g3 to 1 and g4 to 0, the above n0may be regarded as a reserved (maintained for the future) bit (field)according to the prescription given in advance, or the terminal #p maydetermine the above n0 to be an invalid bit (field), or the base stationor AP may obtain the above n0 and determine n0 to be an invalid bit(field).

In the description given above, an embodiment is possible in which eachterminal #p “supports the demodulation of the single-carrier scheme”. Inthis case, the bit (field) of g3 described above is not necessary.

The base station that has received the reception capability notificationsymbol transmitted by the terminal #p described above generates andtransmits a modulated signal on the basis of the reception capabilitynotification symbol, and accordingly the terminal #p is able to receivea transmission signal that can be demodulated. A specific example of theoperation of the base station has been described in embodiments, such asthe third embodiment, the fifth embodiment, and the fifteenthembodiment.

With the embodiment being carried out in the above-described manner, thefollowing example characteristics can be obtained.

Characteristic #1

“A first reception apparatus, where

-   -   the reception apparatus generates control information indicating        a signal receivable by the reception apparatus, the control        information including a first region, a second region, a third        region, and a fourth region,    -   the first region is a region storing information indicating        whether or not it is possible to receive a signal for        transmitting data generated by using a single-carrier scheme and        information indicating whether or not it is possible to receive        a signal generated by using a multi-carrier scheme,    -   the second region is a region storing information indicating        whether or not it is possible to receive a signal generated by        using any one of one or more schemes usable in both or either of        a case of generating a signal by using the single-carrier scheme        and a case of generating a signal by using the multi-carrier        scheme, the third region is    -   in a case of storing, in the first region, information        indicating that it is possible to receive a signal for        transmitting data generated by using the single-carrier scheme,        a region storing information indicating whether or not it is        possible to receive a signal generated by using any one of one        or more schemes usable in a case of generating a signal by using        the single-carrier scheme, and    -   in a case of storing, in the first region, information        indicating that it is impossible to receive a signal for        transmitting data generated by using the single-carrier scheme,        an invalid or reserved region,    -   the fourth region is    -   in a case of storing, in the first region, information        indicating that it is possible to receive a signal for        transmitting data generated by using the multi-carrier scheme, a        region storing information indicating whether or not it is        possible to receive a signal generated by using any one of one        or more schemes usable in a case of generating a signal by using        the multi-carrier scheme, and    -   in a case of storing, in the first region, information        indicating that it is impossible to receive a signal for        transmitting data generated by using the multi-carrier scheme,        an invalid or reserved region, and    -   the reception apparatus generates a control signal from the        control information and transmits the control signal to a        transmission apparatus.”

“The above-described first reception apparatus, where

-   -   the second region includes a fifth region storing information        indicating whether or not it is possible to receive a signal        generated by using the Multiple-Input Multiple-Output (MIMO)        scheme,    -   the second region or the fourth region includes a sixth region        storing information indicating whether or not it is possible to        receive a signal generated by using a phase change scheme for        performing phase change while regularly switching a phase change        value with respect to at least any one of signals of multiple        transmission systems for transmitting data, and    -   the reception apparatus sets a bit located in the sixth region        to a predetermined value in a case of storing, in the first        region, information indicating that it is impossible to receive        a signal for transmitting data generated by using the        multi-carrier scheme, or in a case of storing, in the first        region, information indicating that it is possible to receive a        signal for transmitting data generated by using the        multi-carrier scheme and storing, in the fifth region,        information indicating that it is impossible to receive a signal        of the MIMO scheme.”

“A first transmission apparatus that

-   -   receives the control signal from the above-described first        reception apparatus,    -   demodulates the received control signal to obtain the control        signal, and    -   decides, on the basis of the control signal, a scheme to be used        to generate a signal to be transmitted to the reception        apparatus.”

“The above-described first transmission apparatus, where

-   -   the second region includes a fifth region storing information        indicating whether or not it is possible to receive a signal        generated by using the Multiple-Input Multiple-Output (MIMO)        scheme,    -   the second region or the fourth region includes a sixth region        storing information indicating whether or not it is possible to        receive a signal generated by using a phase change scheme for        performing phase change while regularly switching a phase change        value with respect to at least any one of signals of multiple        transmission systems for transmitting data, and    -   the transmission apparatus decides a scheme to be used to        generate a signal to be transmitted to the reception apparatus        without using a value of a bit located in the sixth region in a        case where the first region includes information indicating that        it is impossible to receive a signal for transmitting data        generated by using the multi-carrier scheme, or in a case where        the first region includes information indicating that it is        possible to receive a signal for transmitting data generated by        using the multi-carrier scheme and the fifth region includes        information indicating that it is impossible to receive a signal        of the MIMO scheme.”

Characteristic #2

“A second reception apparatus, where

-   -   the reception apparatus generates control information indicating        a signal receivable by the reception apparatus, the control        information including a first region, a second region, a third        region, and a fourth region,    -   the first region is a region storing information indicating        whether or not it is possible to receive a signal generated by        using a multi-carrier scheme,    -   the second region is a region storing information indicating        whether or not it is possible to receive a signal generated by        using any one of one or more schemes usable in both or either of        a case of generating a signal by using a single-carrier scheme        and a case of generating a signal by using the multi-carrier        scheme,    -   the third region is a region storing information indicating        whether or not it is possible to receive a signal generated by        using any one of one or more schemes usable in a case of        generating a signal by using the single-carrier scheme,    -   the fourth region is    -   in a case of storing, in the first region, information        indicating that it is possible to receive a signal for        transmitting data generated by using the multi-carrier scheme, a        region storing information indicating whether or not it is        possible to receive a signal generated by using any one of one        or more schemes usable in a case of generating a signal by using        the multi-carrier scheme, and    -   in a case of storing, in the first region, information        indicating that it is impossible to receive a signal for        transmitting data generated by using the multi-carrier scheme,        an invalid or reserved region, and    -   the reception apparatus generates a control signal from the        control information and transmits the control signal to a        transmission apparatus.”

“The above-described second reception apparatus, where

-   -   the second region includes a fifth region storing information        indicating whether or not it is possible to receive a signal        generated by using the Multiple-Input Multiple-Output (MIMO)        scheme,    -   the second region or the fourth region includes a sixth region        storing information indicating whether or not it is possible to        receive a signal generated by using a phase change scheme for        performing phase change while regularly switching a phase change        value with respect to at least any one of signals of multiple        transmission systems for transmitting data, and    -   the reception apparatus sets a bit located in the sixth region        to a predetermined value in a case of storing, in the first        region, information indicating that it is impossible to receive        a signal for transmitting data generated by using the        multi-carrier scheme, or in a case of storing, in the first        region, information indicating that it is possible to receive a        signal for transmitting data generated by using the        multi-carrier scheme and storing, in the fifth region,        information indicating that it is impossible to receive a signal        of the MIMO scheme.”

“A second transmission apparatus that

-   -   receives the control signal from the above-described second        reception apparatus,    -   demodulates the received control signal to obtain the control        signal, and    -   decides, on the basis of the control signal, a scheme to be used        to generate a signal to be transmitted to the reception        apparatus.”

“The above-described second transmission apparatus, where

-   -   the second region includes a fifth region storing information        indicating whether or not it is possible to receive a signal        generated by using the Multiple-Input Multiple-Output (MIMO)        scheme,    -   the second region or the fourth region includes a sixth region        storing information indicating whether or not it is possible to        receive a signal generated by using a phase change scheme for        performing phase change while regularly switching a phase change        value with respect to at least any one of signals of multiple        transmission systems for transmitting data, and    -   the transmission apparatus decides a scheme to be used to        generate a signal to be transmitted to the reception apparatus        without using a value of a bit located in the sixth region in a        case where the first region includes information indicating that        it is impossible to receive a signal for transmitting data        generated by using the multi-carrier scheme, or in a case where        the first region includes information indicating that it is        possible to receive a signal for transmitting data generated by        using the multi-carrier scheme and the fifth region includes        information indicating that it is impossible to receive a signal        of the MIMO scheme.”

In the present embodiment, the configuration in FIG. 80 has beendescribed as an example of the configuration of the reception capabilitynotification symbol 2702 in FIG. 27 , but the configuration is notlimited thereto, and a reception capability notification symboldifferent from that in FIG. 80 may exist. For example, the configurationin FIG. 84 may be used.

In FIG. 84 , the elements that operate similarly to those in FIG. 80 aredenoted by the same numerals, and the description thereof is omitted. InFIG. 84 , the other reception capability notification symbol 9801 isadded as a reception capability notification symbol.

The other reception capability notification symbol 9801 is, for example,a reception capability notification symbol that is not the“single-carrier scheme and OFDM scheme related reception capabilitynotification symbol 9401”, that is not the “single-carrier schemerelated reception capability notification symbol 9402”, and that is notthe “OFDM scheme related reception capability notification symbol 9403”.

Also with such a reception capability notification symbol, theabove-described embodiments can be carried out similarly.

In FIG. 80 , a description has been given of an example of the receptioncapability notification symbol in which the “single-carrier scheme andOFDM scheme related reception capability notification symbol 9401”, the“single-carrier scheme related reception capability notification symbol9402”, and the “OFDM scheme related reception capability notificationsymbol 9403” are arranged in this order, but the reception capabilitynotification symbol is not limited thereto. An example thereof will bedescribed below.

In FIG. 80 , it is assumed that bit r0, bit r1, bit r2, and bit r3 existas the “single-carrier scheme and OFDM scheme related receptioncapability notification symbol 9401”. Also, it is assumed that bit r4,bit r5, bit r6, and bit r7 exist as the “single-carrier scheme relatedreception capability notification symbol 9402”. Also, it is assumed thatbit r8, bit r9, bit r10, and bit r11 exist as the “OFDM scheme relatedreception capability notification symbol 9403”.

In the case of FIG. 80 , it is assumed that bit r1, bit r2, bit r3, bitr4, bit r5, bit r6, bit r7, bit r8, bit r9, bit r10, and bit r11 arearranged in order, and are located in this order with respect to aframe, for example.

As another method, a bit sequence in which the order of “bit r1, bit r2,bit r3, bit r4, bit r5, bit r6, bit r7, bit r8, bit r9, bit r10, and bitr11” is changed, for example, a bit sequence of “bit r7, bit r2, bit r4,bit r6, bit r1, bit r8, bit r9, bit r5, bit r10, bit r3, and bit r11”may be located in this order with respect to a frame. The order in thebit sequence is not limited to this example.

In addition, in FIG. 80 , it is assumed that field s0, field s1, fields2, and field s3 exist as the “single-carrier scheme and OFDM schemerelated reception capability notification symbol 9401”. Also, it isassumed that field s4, field s5, field s6, and field s7 exist as the“single-carrier scheme related reception capability notification symbol9402”. Also, it is assumed that field s8, field s9, field s10, and fields11 exist as the “OFDM scheme related reception capability notificationsymbol 9403”. It is assumed that a “field” is made up of one or morebits.

In the case of FIG. 80 , it is assumed that field s1, field s2, fields3, field s4, field s5, field s6, field s7, field s8, field s9, fields10, and field s11 are arranged in order, and are located in this orderwith respect to a frame, for example.

As another method, a field sequence in which the order of “field s1,field s2, field s3, field s4, field s5, field s6, field s7, field s8,field s9, field s10, and field s11” is changed, for example, a fieldsequence of “field s7, field s2, field s4, field s6, field s1, field s8,field s9, field s5, field s10, field s3, and field s11” may be locatedin this order with respect to a frame. The order in the field sequenceis not limited to this example.

In FIG. 84 , a description has been given of an example of the receptioncapability notification symbol in which the “single-carrier scheme andOFDM scheme related reception capability notification symbol 9401”, the“single-carrier scheme related reception capability notification symbol9402”, the “OFDM scheme related reception capability notification symbol9403”, and the “other reception capability notification symbol 9801” arearranged in this order, but the reception capability notification symbolis not limited thereto. An example thereof will be described below.

In FIG. 84 , it is assumed that bit r0, bit r1, bit r2, and bit r3 existas the “single-carrier scheme and OFDM scheme related receptioncapability notification symbol 9401”. Also, it is assumed that bit r4,bit r5, bit r6, and bit r7 exist as the “single-carrier scheme relatedreception capability notification symbol 9402”. Also, it is assumed thatbit r8, bit r9, bit r10, and bit r11 exist as the “OFDM scheme relatedreception capability notification symbol 9403”. Also, it is assumed thatbit r12, bit r13, bit r14, and bit r15 exist as the “other receptioncapability notification symbol 9801”.

In the case of FIG. 84 , it is assumed that bit r1, bit r2, bit r3, bitr4, bit r5, bit r6, bit r7, bit r8, bit r9, bit r10, bit r11, bit r12,bit r13, bit r14, and bit r15 are arranged in order, and are located inthis order with respect to a frame, for example.

As another method, a bit sequence in which the order of “bit r1, bit r2,bit r3, bit r4, bit r5, bit r6, bit r7, bit r8, bit r9, bit r10, bitr11, bit r12, bit r13, bit r14, and bit r15” is changed, for example, abit sequence of “bit r7, bit r2, bit r4, bit r6, bit r13, bit r1, bitr8, bit r12, bit r9, bit r5, bit r10, bit r3, bit r15, bit r11, and bitr14” may be located in this order with respect to a frame. The order inthe bit sequence is not limited to this example.

In addition, in FIG. 84 , it is assumed that field s0, field s1, fields2, and field s3 exist as the “single-carrier scheme and OFDM schemerelated reception capability notification symbol 9401”. Also, it isassumed that field s4, field s5, field s6, and field s7 exist as the“single-carrier scheme related reception capability notification symbol9402”. Also, it is assumed that field s8, field s9, field s10, and fields11 exist as the “OFDM scheme related reception capability notificationsymbol 9403”. Also, it is assumed that field s12, field s13, field s14,and field s15 exist as the “other reception capability notificationsymbol 9801”. It is assumed that a “field” is made up of one or morebits.

In the case of FIG. 84 , it is assumed that field s1, field s2, fields3, field s4, field s5, field s6, field s7, field s8, field s9, fields10, field s11, field s12, field s13, field s14, and field s15 arearranged in order, and are located in this order with respect to aframe, for example.

As another method, a field sequence in which the order of “field s1,field s2, field s3, field s4, field s5, field s6, field s7, field s8,field s9, field s10, field s11, field s12, field s13, field s14, andfield s15” is changed, for example, a field sequence of “field s7, fields2, field s4, field s6, field s13, field s1, field s8, field s12, fields9, field s5, field s10, field s3, field s15, field s1l, and field s14”may be located in this order with respect to a frame. The order in thefield sequence is not limited to this example.

It is not always explicitly indicated that the information transmittedby the “single-carrier scheme related reception capability notificationsymbol” is information directed to the single-carrier scheme. Theinformation transmitted by the “single-carrier scheme related receptioncapability notification symbol” described in the present embodiment is,for example, information for giving a notice about a selectable schemein a case where the transmission apparatus transmits a signal in thesingle-carrier scheme. In another example, the information transmittedby the “single-carrier scheme related reception capability notificationsymbol” described in the present embodiment is, for example, informationthat is not used (ignored) to select a scheme to be used fortransmitting a signal in a case where the transmission apparatustransmits a signal in a scheme other than the single-carrier scheme,such as the OFDM scheme. In still another example, the informationtransmitted by the “single-carrier scheme related reception capabilitynotification symbol” described in the present embodiment is, forexample, information that is transmitted by using a region determined tobe an invalid region or reserved region by the transmission apparatus orthe reception apparatus in a case where the reception apparatus does notsupport the reception of a signal of the single-carrier scheme (notifiesthe transmission apparatus of non-support). In the above description,the term “single-carrier scheme related reception capabilitynotification symbol 9402” is used, but the term is not limited thereto,and another term may be used. For example, the term “symbol indicatingthe reception capability of the (first) terminal #p” may be used. Inaddition, the “single-carrier scheme related reception capabilitynotification symbol 9402” may include information other than informationfor giving a notice about a receivable signal.

Likewise, it is not always explicitly indicated that the informationtransmitted by the “OFDM scheme related reception capabilitynotification symbol” is information directed to the OFDM scheme. Theinformation transmitted by the “OFDM scheme related reception capabilitynotification symbol” described in the present embodiment is, forexample, information for giving a notice about a selectable scheme in acase where the transmission apparatus transmits a signal in the OFDMscheme. In another example, the information transmitted by the “OFDMscheme related reception capability notification symbol” described inthe present embodiment is, for example, information that is not used(ignored) to select a scheme to be used for transmitting a signal in acase where the transmission apparatus transmits a signal in a schemeother than the OFDM scheme, such as the single-carrier scheme. In stillanother example, the information transmitted by the “OFDM scheme relatedreception capability notification symbol” described in the presentembodiment is, for example, information that is transmitted by using aregion determined to be an invalid region or reserved region by thetransmission apparatus or the reception apparatus in a case where thereception apparatus does not support the reception of a signal of theOFDM scheme. In the above description, the term “OFDM scheme relatedreception capability notification symbol 9403” is used, but the term isnot limited thereto, and another term may be used. For example, the term“symbol indicating the reception capability of the (second) terminal #p”may be used. In addition, the “OFDM scheme related reception capabilitynotification symbol 9403” may include information other than informationfor giving a notice about a receivable signal.

The term “single-carrier scheme and OFDM scheme related receptioncapability notification symbol 9401” is used, but the term is notlimited thereto, and another term may be used. For example, the term“symbol indicating the reception capability of the (third) terminal #p”may be used. In addition, the “single-carrier scheme and OFDM schemerelated reception capability notification symbol 9401” may includeinformation other than information for giving a notice about areceivable signal.

As in the present embodiment, the terminal #p forms and transmits areception capability notification symbol, and the base station receivesthe reception capability notification symbol, generates a modulatedsignal by considering the effectiveness of the value thereof, andtransmits the modulated signal. Accordingly, the terminal #p is able toreceive the modulated signal that can be demodulated, and is thus ableto appropriately obtain data and improve the data reception quality. Inaddition, the terminal #p generates data of each bit (each field) of thereception capability notification symbol while determining theeffectiveness of the bit (the field), and is thus able to reliablytransmit the reception capability notification symbol to the basestation and improve the communication quality.

In the present embodiment, in a case where the base station or AP doesnot support the transmission of a modulated signal using the robustcommunication method described in the twelfth embodiment and the presentembodiment, the base station or AP does not transmit a modulated signalusing the above-described robust communication method even if theterminal #p supports the demodulation of the above-described robustcommunication method.

Twenty-fourth Embodiment

In the present embodiment, a description will be given of another methodfor carrying out the operation of the terminal #p described in the thirdembodiment, the fifth embodiment, and the fifteenth embodiment.

In the present embodiment, a description will be given of an example inwhich the base station or AP is able to switch between the case oftransmitting a modulated signal of the OFDM scheme and the case oftransmitting a modulated signal of the Orthogonal Frequency-DivisionMultiple Access (OFDMA) scheme, and the terminal #p supports/does notsupport demodulation of a modulated signal of OFDMA.

First, a description will be given of the case of transmitting amodulated signal of the OFDM scheme and the case of transmitting amodulated signal of the OFDMA scheme.

An example of the frame configuration in a case where the base stationor AP transmits a modulated signal of the OFDM scheme may be the frameconfiguration in FIG. 36 . FIG. 36 has been described in the fifthembodiment, for example, and thus the detailed description thereof isomitted. The frame configuration in FIG. 36 is a frame configuration fortransmitting a modulated signal of a single stream.

In a case where a modulated signal of the OFDM scheme is beingtransmitted, a situation does not occur where the terminal #p as theaddress varies according to a carrier in a certain time interval. Thus,for example, the symbols existing in the frame configuration in FIG. 36are symbols addressed to a certain terminal #p. For another example, ina case where the base station or AP transmits multiple modulated signalsby using multiple antennas, the frame configurations of the modulatedsignals of the OFDM scheme are “FIGS. 8 and 9 ”. In the case of theframe configurations in “FIGS. 8 and 9 ”, the frames in FIGS. 8 and 9correspond to the symbols addressed to a certain terminal #p.

A description will be given of a case where the base station or APtransmits a modulated signal of the OFDMA scheme. In a case where amodulated signal of the OFDMA scheme is being transmitted, a situationmay occur where the terminal #p as the address varies according to acarrier in a certain time interval.

For example, it is assumed that, in a case where the base station or APtransmits a modulated signal of the OFDM scheme having the frameconfiguration in FIG. 36 , the data symbols 3602 exist from time 5,carrier 1 to carrier 12 from time 5 are the symbols addressed to aterminal #A, carrier 13 to carrier 24 from time 5 are the symbolsaddressed to a terminal #B, and carrier 25 to carrier 36 from time 5 arethe symbols addressed to a terminal #C. However, the relationshipsbetween carriers and the terminals #p as addressees are not limitedthereto. For example, a method for allocating the symbols in carrier 1to carrier 36 from time 5 to two or more terminals is conceivable. Also,it is assumed that the other symbols 3603 include information about therelationships between carriers and terminals as addresses. Thus, eachterminal #p is able to learn the relationships between carriers andterminals as addresses by obtaining the other symbols 3603, andaccordingly each terminal is able to learn the portion in the framewhere the symbols addressed to the terminal exist. The frameconfiguration in FIG. 36 is an example when the base station or AP istransmitting a modulated signal of a single stream, and the frameconfiguration is not limited to the configuration in FIG. 36 .

For another example, a description will be given of a method forconfiguring a modulated signal of the OFDMA scheme when the base stationor AP transmits multiple modulated signals by using multiple antennas.For example, a case where the base station or AP transmits multiplemodulated signals having the frame configurations in “FIGS. 8 and 9 ” byusing multiple antennas is considered.

At this time, in FIG. 8 , it is assumed that carrier 1 to carrier 12from time 5 are the symbols addressed to the terminal #A, carrier 13 tocarrier 24 from time 5 are the symbols addressed to the terminal #B, andcarrier 25 to carrier 36 from time 5 are the symbols addressed to theterminal #C. However, the relationships between carriers and theterminals #p as addressees are not limited thereto. For example, amethod for allocating the symbols in carrier 1 to carrier 36 from time 5to two or more terminals is conceivable. Also, it is assumed that theother symbols 603 include information about the relationships betweencarriers and terminals as addresses.

Likewise, in FIG. 9 , it is assumed that carrier 1 to carrier 12 fromtime 5 are the symbols addressed to the terminal #A, carrier 13 tocarrier 24 from time 5 are the symbols addressed to the terminal #B, andcarrier 25 to carrier 36 from time 5 are the symbols addressed to theterminal #C. However, the relationships between carriers and theterminals #p as addressees are not limited thereto. For example, amethod for allocating the symbols in carrier 1 to carrier 36 from time 5to two or more terminals is conceivable. Also, it is assumed that theother symbols 703 include information about the relationships betweencarriers and terminals as addresses.

Thus, each terminal #p is able to learn the relationships betweencarriers and terminals as addresses by obtaining the other symbols 603and/or the other symbols 703, and accordingly each terminal is able tolearn the portion in the frame where the symbols addressed to theterminal exist.

The base station or AP has the configuration illustrated in FIG. 22 ,for example, and receives a signal transmitted by the terminal #p. Theconfiguration in FIG. 22 has already been described, and thus thedescription thereof is omitted.

FIG. 34 is an example of the configuration of the terminal #p, which isa communication partner of the base station or AP. The description hasalready been given, and thus the description is omitted.

FIG. 27 illustrates an example of communication between the base stationor AP and the terminal #p. The details thereof have been described inthe third embodiment, the fifth embodiment, the fifteenth embodiment,and so forth, and thus the description thereof is omitted.

FIG. 80 illustrates a specific example configuration of the receptioncapability notification symbol 2702 transmitted by the terminal #pillustrated in FIG. 27 .

Before describing FIG. 80 , a description will be given of theconfiguration of the terminal #p that exists as the terminal #p thatcommunicates with the base station or AP.

In the present embodiment, it is assumed that the following types ofterminals #p may exist.

Terminal Type #1:

It is possible to demodulate a modulated signal of the single-carrierscheme and single-stream transmission.

Terminal Type #2:

It is possible to demodulate a modulated signal of the single-carrierscheme and single-stream transmission. Additionally, it is possible toreceive and demodulate multiple modulated signals of the single-carrierscheme transmitted by a communication partner by using multipleantennas.

Terminal Type #3:

It is possible to demodulate a modulated signal of the single-carrierscheme and single-stream transmission. Furthermore, it is possible todemodulate a modulated signal of the OFDM scheme and single-streamtransmission.

Terminal Type #4:

It is possible to demodulate a modulated signal of the single-carrierscheme and single-stream transmission. Additionally, it is possible toreceive and demodulate multiple modulated signals of the single-carrierscheme transmitted by a communication partner by using multipleantennas. Furthermore, it is possible to demodulate a modulated signalof the OFDM scheme and single-stream transmission. Additionally, it ispossible to receive and demodulate multiple modulated signals of theOFDM scheme transmitted by a communication partner by using multipleantennas.

Terminal Type #5:

It is possible to demodulate a modulated signal of the OFDM scheme andsingle-stream transmission.

Terminal Type #6:

It is possible to demodulate a modulated signal of the OFDM scheme andsingle-stream transmission. Additionally, it is possible to receive anddemodulate multiple modulated signals of the OFDM scheme transmitted bya communication partner by using multiple antennas.

In the present embodiment, for example, it is assumed that the terminals#p of the terminal type #1 to the terminal type #6 may communicate withthe base station or AP. Note that the base station or AP may communicatewith the terminal #p of a type different from the terminal type #1 tothe terminal type #6.

In view of the above, the reception capability notification symbol inFIG. 80 will be described.

FIG. 80 illustrates an example of a specific configuration of thereception capability notification symbol 2702 transmitted by theterminal #p illustrated in FIG. 27 .

As illustrated in FIG. 80 , the “single-carrier scheme and OFDM schemerelated reception capability notification symbol 9401”, the“single-carrier scheme related reception capability notification symbol9402”, and the “OFDM scheme related reception capability notificationsymbol 9403” constitute a reception capability notification symbol. Areception capability notification symbol other than those illustrated inFIG. 80 may be included.

It is assumed that the “single-carrier scheme and OFDM scheme relatedreception capability notification symbol 9401” includes data fornotifying a communication partner (in this case, for example, the basestation or AP) of the reception capability for both a modulated signalof the single-carrier scheme and a modulated signal of the OFDM scheme.

Also, it is assumed that the “single-carrier scheme related receptioncapability notification symbol 9402” includes data for notifying acommunication partner (in this case, for example, the base station orAP) of the reception capability for a modulated signal of thesingle-carrier scheme.

It is assumed that the “OFDM scheme related reception capabilitynotification symbol 9403” includes data for notifying a communicationpartner (in this case, for example, the base station or AP) of thereception capability for a modulated signal of the OFDM scheme.

FIG. 81 illustrates an example of the configuration of the“single-carrier scheme and OFDM scheme related reception capabilitynotification symbol 9401” illustrated in FIG. 80 .

It is assumed that the “single-carrier scheme and OFDM scheme relatedreception capability notification symbol 9401” illustrated in FIG. 80includes the data 9501 about “support of SISO or MIMO (MISO)”, the data9502 about “supported error-correcting coding schemes”, and the data9503 about “support status of single-carrier scheme and OFDM scheme” inFIG. 81 .

When the data 9501 about “support of SISO or MIMO (MISO)” is g0 and g1,the terminal #p performs the following operation, for example.

For example, it is assumed that, in a case where the communicationpartner of the terminal #p transmits a modulated signal of a singlestream and the terminal #p is able to demodulate the modulated signal,the terminal #p sets g0=1 and g1=0, and the terminal #p transmits areception capability notification symbol including g0 and g1.

It is assumed that, in a case where the communication partner of theterminal #p transmits multiple different modulated signals by usingmultiple antennas and the terminal #p is able to demodulate themodulated signals, the terminal #p sets g0=0 and g1=1, and the terminal#p transmits a reception capability notification symbol including g0 andg1.

It is assumed that, in a case where the communication partner of theterminal #p transmits a modulated signal of a single stream and theterminal #p is able to demodulate the modulated signal, and in a casewhere the communication partner of the terminal #p transmits multipledifferent modulated signals by using multiple antennas and the terminal#p is able to demodulate the modulated signals, the terminal #p setsg0=1 and g1=1, and the terminal #p transmits a reception capabilitynotification symbol including g0 and g1.

When the data 9502 about “supported error-correcting coding schemes” isg2, the terminal #p performs the following operation, for example.

For example, it is assumed that, in a case where the terminal #p is ableto perform error-correcting decoding on data of a first error-correctingcoding scheme, the terminal #p sets g2=0, and the terminal #p transmitsa reception capability notification symbol including g2.

It is assumed that, in a case where the terminal #p is able to performerror-correcting decoding on data of the first error-correcting codingscheme and is able to perform error-correcting decoding on data of asecond error-correcting coding scheme, the terminal #p sets g2=1, andthe terminal #p transmits a reception capability notification symbolincluding g2.

As another case, it is assumed that each terminal #p is able to performerror-correcting decoding on data of the first error-correcting codingscheme. Furthermore, in a case where the terminal #p is able to performerror-correcting decoding on data of the second error-correcting codingscheme, the terminal #p sets g2=1, and in a case where the terminal #pdoes not support error-correcting decoding on data of the seconderror-correcting coding scheme, the terminal #p sets g2=0. It is assumedthat the terminal #p transmits a reception capability notificationsymbol including g2.

It is assumed that the first error-correcting coding scheme and thesecond error-correcting coding scheme are different schemes. Forexample, it is assumed that the block length (code length) of the firsterror-correcting coding scheme is A bits (A is an integer equal to orgreater than 2), the block length (code length) of the seconderror-correcting coding scheme is B bits (B is an integer equal to orgreater than 2), and A≠B holds. However, an example of the differentschemes is not limited thereto, and the error-correcting code used inthe first error-correcting coding scheme and the error-correcting codeused in the second error-correcting coding scheme may be different fromeach other.

When the data 9503 about “support status of single-carrier scheme andOFDM scheme” is g3 and g4, the terminal #p performs the followingoperation, for example.

For example, it is assumed that, in a case where the terminal #p is ableto demodulate a modulated signal of the single-carrier scheme, theterminal #p sets g3=1 and g4=0 (in this case, the terminal #p does notsupport demodulation of a modulated signal of OFDM), and the terminal #ptransmits a reception capability notification symbol including g3 andg4.

It is assumed that, in a case where the terminal #p is able todemodulate a modulated signal of the OFDM scheme, the terminal #p setsg3=0 and g4=1 (in this case, the terminal #p does not supportdemodulation of a modulated signal of the single-carrier scheme), andthe terminal #p transmits a reception capability notification symbolincluding g3 and g4.

It is assumed that, in a case where the terminal #p is able todemodulate a modulated signal of the single-carrier scheme and is ableto demodulate a modulated signal of the OFDM scheme, the terminal #psets g3=1 and g4=1, and the terminal #p transmits a reception capabilitynotification symbol including g3 and g4.

FIG. 82 illustrates an example of the configuration of the“single-carrier scheme related reception capability notification symbol9402” illustrated in FIG. 80 .

It is assumed that the “single-carrier scheme related receptioncapability notification symbol 9402” illustrated in FIG. 80 includes thedata 9601 about “schemes supported by single-carrier scheme” in FIG. 82.

When the data 9601 about “schemes supported by single-carrier scheme” ish0 and h1, the terminal #p performs the following operation, forexample.

For example, it is assumed that, in a case where the communicationpartner of the terminal #p transmits a modulated signal by performingchannel bonding and the terminal #p is able to demodulate the modulatedsignal, the terminal #p sets h0=1, whereas in a case where the terminal#p does not support demodulation of the modulated signal, the terminal#p sets h0=0, and the terminal #p transmits a reception capabilitynotification symbol including h0.

It is assumed that, in a case where the communication partner of theterminal #p transmits a modulated signal by performing channelaggregation and the terminal #p is able to demodulate the modulatedsignal, the terminal #p sets h1=1, whereas in a case where the terminal#p does not support demodulation of the modulated signal, the terminal#p sets h1=0, and the terminal #p transmits a reception capabilitynotification symbol including h1.

In a case where the terminal #p sets g3 to 0 and g4 to 1, since theterminal #p does not support demodulation of a modulated signal of thesingle-carrier scheme, the bit (field) of h0 is an invalid bit (field),and also the bit (field) of h1 is an invalid bit (field).

In a case where the terminal #p sets g3 to 0 and g4 to 1, the above h0and h1 may be regarded as a reserved (maintained for the future) bit(field) according to the prescription given in advance, or the terminal#p may determine the above h0 and h1 to be an invalid bit (field) (maydetermine the above h0 or h1 to be an invalid bit (field)), or the basestation or AP may obtain the above h0 and h1 and determine h0 and h1 tobe an invalid bit (field) (may determine the above h0 or h1 to be aninvalid bit (field)).

According to the description given above, there is a case where theterminal #p sets g3 to 0 and g4 to 1, that is, a case where the terminal#p does not support demodulation of a modulated signal of thesingle-carrier scheme, but an embodiment is possible in which eachterminal #p “supports the demodulation of the single-carrier scheme”. Inthis case, the bit (field) of g3 described above is not necessary.

FIG. 88 illustrates an example of the configuration of the “OFDM schemerelated reception capability notification symbol 9403” illustrated inFIG. 80 .

It is assumed that the “OFDM scheme related reception capabilitynotification symbol 9403” illustrated in FIG. 80 includes the data 9701about “schemes supported by OFDM scheme” in FIG. 88 .

In addition, it is assumed that the data 9701 about “schemes supportedby OFDM scheme” includes data 10302 about “support/not supportdemodulation of OFDMA scheme” indicating “whether the terminal #p isable to demodulate a modulated signal of the OFDMA scheme when the basestation or AP as a communication partner transmits the modulated signalof the OFDMA scheme”.

For example, when the data 10302 about “support/not support demodulationof OFDMA scheme” is p0, the terminal #p performs the followingoperation, for example.

It is assumes that, in a case where the terminal #p does not supportdemodulation of a modulated signal of the OFDMA scheme, the terminal #psets p0=0, and the terminal #p transmits a reception capabilitynotification symbol including p0.

Also, it is assumed that, in a case where the terminal #p supportsdemodulation of a modulated signal of the OFDMA scheme, the terminal #psets p0=1, and the terminal #p transmits a reception capabilitynotification symbol including p0.

In a case where the terminal #p sets g3 to 1 and g4 to 0, since theterminal #p does not support demodulation of a modulated signal of theOFDM scheme, the bit (field) of p0 is an invalid bit (field).

In a case where the terminal #p sets g3 to 1 and g4 to 0, the above p0may be regarded as a reserved (maintained for the future) bit (field)according to the prescription given in advance, or the terminal #p maydetermine the above p0 to be an invalid bit (field), or the base stationor AP may obtain the above p0 and determine p0 to be an invalid bit(field).

In the description given above, an embodiment is possible in which eachterminal #p “supports the demodulation of the single-carrier scheme”. Inthis case, the bit (field) of g3 described above is not necessary.

The base station that has received the reception capability notificationsymbol transmitted by the terminal #p described above generates andtransmits a modulated signal on the basis of the reception capabilitynotification symbol, and accordingly the terminal #p is able to receivea transmission signal that can be demodulated. A specific example of theoperation of the base station has been described in embodiments, such asthe third embodiment, the fifth embodiment, and the fifteenthembodiment.

With the embodiment being carried out in the above-described manner, thefollowing example characteristics can be obtained.

Characteristic #1

“A first reception apparatus, where

-   -   the reception apparatus generates control information indicating        a signal receivable by the reception apparatus, the control        information including a first region, a second region, a third        region, and a fourth region,    -   the first region is a region storing information indicating        whether or not it is possible to receive a signal for        transmitting data generated by using a single-carrier scheme and        information indicating whether or not it is possible to receive        a signal generated by using a multi-carrier scheme,    -   the second region is a region storing information indicating        whether or not it is possible to receive a signal generated by        using any one of one or more schemes usable in both or either of        a case of generating a signal by using the single-carrier scheme        and a case of generating a signal by using the multi-carrier        scheme,    -   the third region is    -   in a case of storing, in the first region, information        indicating that it is possible to receive a signal for        transmitting data generated by using the single-carrier scheme,        a region storing information indicating whether or not it is        possible to receive a signal generated by using any one of one        or more schemes usable in a case of generating a signal by using        the single-carrier scheme, and    -   in a case of storing, in the first region, information        indicating that it is impossible to receive a signal for        transmitting data generated by using the single-carrier scheme,        an invalid or reserved region,    -   the fourth region is    -   in a case of storing, in the first region, information        indicating that it is possible to receive a signal for        transmitting data generated by using the multi-carrier scheme, a        region storing information indicating whether or not it is        possible to receive a signal generated by using any one of one        or more schemes usable in a case of generating a signal by using        the multi-carrier scheme, and    -   in a case of storing, in the first region, information        indicating that it is impossible to receive a signal for        transmitting data generated by using the multi-carrier scheme,        an invalid or reserved region, and    -   the reception apparatus generates a control signal from the        control information and transmits the control signal to a        transmission apparatus.”

“The above-described first reception apparatus, where

-   -   the second region includes a fifth region storing information        indicating whether or not it is possible to receive a signal        generated by using the Multiple-Input Multiple-Output (MIMO)        scheme,    -   the second region or the fourth region includes a sixth region        storing information indicating whether or not it is possible to        receive a signal generated by using a phase change scheme for        performing phase change while regularly switching a phase change        value with respect to at least any one of signals of multiple        transmission systems for transmitting data, and    -   the reception apparatus sets a bit located in the sixth region        to a predetermined value in a case of storing, in the first        region, information indicating that it is impossible to receive        a signal for transmitting data generated by using the        multi-carrier scheme, or in a case of storing, in the first        region, information indicating that it is possible to receive a        signal for transmitting data generated by using the        multi-carrier scheme and storing, in the fifth region,        information indicating that it is impossible to receive a signal        of the MIMO scheme.”

“A first transmission apparatus that

-   -   receives the control signal from the above-described first        reception apparatus,    -   demodulates the received control signal to obtain the control        signal, and    -   decides, on the basis of the control signal, a scheme to be used        to generate a signal to be transmitted to the reception        apparatus.”

“The above-described first transmission apparatus, where

-   -   the second region includes a fifth region storing information        indicating whether or not it is possible to receive a signal        generated by using the Multiple-Input Multiple-Output (MIMO)        scheme,    -   the second region or the fourth region includes a sixth region        storing information indicating whether or not it is possible to        receive a signal generated by using a phase change scheme for        performing phase change while regularly switching a phase change        value with respect to at least any one of signals of multiple        transmission systems for transmitting data, and    -   the transmission apparatus decides a scheme to be used to        generate a signal to be transmitted to the reception apparatus        without using a value of a bit located in the sixth region in a        case where the first region includes information indicating that        it is impossible to receive a signal for transmitting data        generated by using the multi-carrier scheme, or in a case where        the first region includes information indicating that it is        possible to receive a signal for transmitting data generated by        using the multi-carrier scheme and the fifth region includes        information indicating that it is impossible to receive a signal        of the MIMO scheme.”

Characteristic #2

“A second reception apparatus, where

-   -   the reception apparatus generates control information indicating        a signal receivable by the reception apparatus, the control        information including a first region, a second region, a third        region, and a fourth region,    -   the first region is a region storing information indicating        whether or not it is possible to receive a signal generated by        using a multi-carrier scheme,    -   the second region is a region storing information indicating        whether or not it is possible to receive a signal generated by        using any one of one or more schemes usable in both or either of        a case of generating a signal by using a single-carrier scheme        and a case of generating a signal by using the multi-carrier        scheme,    -   the third region is a region storing information indicating        whether or not it is possible to receive a signal generated by        using any one of one or more schemes usable in a case of        generating a signal by using the single-carrier scheme,    -   the fourth region is    -   in a case of storing, in the first region, information        indicating that it is possible to receive a signal for        transmitting data generated by using the multi-carrier scheme, a        region storing information indicating whether or not it is        possible to receive a signal generated by using any one of one        or more schemes usable in a case of generating a signal by using        the multi-carrier scheme, and    -   in a case of storing, in the first region, information        indicating that it is impossible to receive a signal for        transmitting data generated by using the multi-carrier scheme,        an invalid or reserved region, and    -   the reception apparatus generates a control signal from the        control information and transmits the control signal to a        transmission apparatus.”

“The above-described second reception apparatus, where

-   -   the second region includes a fifth region storing information        indicating whether or not it is possible to receive a signal        generated by using the Multiple-Input Multiple-Output (MIMO)        scheme,    -   the second region or the fourth region includes a sixth region        storing information indicating whether or not it is possible to        receive a signal generated by using a phase change scheme for        performing phase change while regularly switching a phase change        value with respect to at least any one of signals of multiple        transmission systems for transmitting data, and    -   the reception apparatus sets a bit located in the sixth region        to a predetermined value in a case of storing, in the first        region, information indicating that it is impossible to receive        a signal for transmitting data generated by using the        multi-carrier scheme, or in a case of storing, in the first        region, information indicating that it is possible to receive a        signal for transmitting data generated by using the        multi-carrier scheme and storing, in the fifth region,        information indicating that it is impossible to receive a signal        of the MIMO scheme.”

“A second transmission apparatus that

-   -   receives the control signal from the above-described second        reception apparatus,    -   demodulates the received control signal to obtain the control        signal, and    -   decides, on the basis of the control signal, a scheme to be used        to generate a signal to be transmitted to the reception        apparatus.”

“The above-described second transmission apparatus, where

-   -   the second region includes a fifth region storing information        indicating whether or not it is possible to receive a signal        generated by using the Multiple-Input Multiple-Output (MIMO)        scheme,    -   the second region or the fourth region includes a sixth region        storing information indicating whether or not it is possible to        receive a signal generated by using a phase change scheme for        performing phase change while regularly switching a phase change        value with respect to at least any one of signals of multiple        transmission systems for transmitting data, and    -   the transmission apparatus decides a scheme to be used to        generate a signal to be transmitted to the reception apparatus        without using a value of a bit located in the sixth region in a        case where the first region includes information indicating that        it is impossible to receive a signal for transmitting data        generated by using the multi-carrier scheme, or in a case where        the first region includes information indicating that it is        possible to receive a signal for transmitting data generated by        using the multi-carrier scheme and the fifth region includes        information indicating that it is impossible to receive a signal        of the MIMO scheme.”

In the present embodiment, the configuration in FIG. 80 has beendescribed as an example of the configuration of the reception capabilitynotification symbol 2702 in FIG. 27 , but the configuration is notlimited thereto, and a reception capability notification symboldifferent from that in FIG. 80 may exist. For example, the configurationin FIG. 84 may be used.

In FIG. 84 , the elements that operate similarly to those in FIG. 80 aredenoted by the same numerals, and the description thereof is omitted. InFIG. 84 , the other reception capability notification symbol 9801 isadded as a reception capability notification symbol.

The other reception capability notification symbol 9801 is, for example,a reception capability notification symbol that is not the“single-carrier scheme and OFDM scheme related reception capabilitynotification symbol 9401”, that is not the “single-carrier schemerelated reception capability notification symbol 9402”, and that is notthe “OFDM scheme related reception capability notification symbol 9403”.

Also with such a reception capability notification symbol, theabove-described embodiments can be carried out similarly.

In FIG. 80 , a description has been given of an example of the receptioncapability notification symbol in which the “single-carrier scheme andOFDM scheme related reception capability notification symbol 9401”, the“single-carrier scheme related reception capability notification symbol9402”, and the “OFDM scheme related reception capability notificationsymbol 9403” are arranged in this order, but the reception capabilitynotification symbol is not limited thereto. An example thereof will bedescribed below.

In FIG. 80 , it is assumed that bit r0, bit r1, bit r2, and bit r3 existas the “single-carrier scheme and OFDM scheme related receptioncapability notification symbol 9401”. Also, it is assumed that bit r4,bit r5, bit r6, and bit r7 exist as the “single-carrier scheme relatedreception capability notification symbol 9402”. Also, it is assumed thatbit r8, bit r9, bit r10, and bit r11 exist as the “OFDM scheme relatedreception capability notification symbol 9403”.

In the case of FIG. 80 , it is assumed that bit r1, bit r2, bit r3, bitr4, bit r5, bit r6, bit r7, bit r8, bit r9, bit r10, and bit r11 arearranged in order, and are located in this order with respect to aframe, for example.

As another method, a bit sequence in which the order of “bit r1, bit r2,bit r3, bit r4, bit r5, bit r6, bit r7, bit r8, bit r9, bit r10, and bitr11” is changed, for example, a bit sequence of “bit r7, bit r2, bit r4,bit r6, bit r1, bit r8, bit r9, bit r5, bit r10, bit r3, and bit r11”may be located in this order with respect to a frame. The order in thebit sequence is not limited to this example.

In addition, in FIG. 80 , it is assumed that field s0, field s1, fields2, and field s3 exist as the “single-carrier scheme and OFDM schemerelated reception capability notification symbol 9401”. Also, it isassumed that field s4, field s5, field s6, and field s7 exist as the“single-carrier scheme related reception capability notification symbol9402”. Also, it is assumed that field s8, field s9, field s10, and fields11 exist as the “OFDM scheme related reception capability notificationsymbol 9403”. It is assumed that a “field” is made up of one or morebits.

In the case of FIG. 80 , it is assumed that field s1, field s2, fields3, field s4, field s5, field s6, field s7, field s8, field s9, fields10, and field s11 are arranged in order, and are located in this orderwith respect to a frame, for example.

As another method, a field sequence in which the order of “field s1,field s2, field s3, field s4, field s5, field s6, field s7, field s8,field s9, field s10, and field s11” is changed, for example, a fieldsequence of “field s7, field s2, field s4, field s6, field s1, field s8,field s9, field s5, field s10, field s3, and field s11” may be locatedin this order with respect to a frame. The order in the field sequenceis not limited to this example.

In FIG. 84 , a description has been given of an example of the receptioncapability notification symbol in which the “single-carrier scheme andOFDM scheme related reception capability notification symbol 9401”, the“single-carrier scheme related reception capability notification symbol9402”, the “OFDM scheme related reception capability notification symbol9403”, and the “other reception capability notification symbol 9801” arearranged in this order, but the reception capability notification symbolis not limited thereto. An example thereof will be described below.

In FIG. 84 , it is assumed that bit r0, bit r1, bit r2, and bit r3 existas the “single-carrier scheme and OFDM scheme related receptioncapability notification symbol 9401”. Also, it is assumed that bit r4,bit r5, bit r6, and bit r7 exist as the “single-carrier scheme relatedreception capability notification symbol 9402”. Also, it is assumed thatbit r8, bit r9, bit r10, and bit r11 exist as the “OFDM scheme relatedreception capability notification symbol 9403”. Also, it is assumed thatbit r12, bit r13, bit r14, and bit r15 exist as the “other receptioncapability notification symbol 9801”.

In the case of FIG. 84 , it is assumed that bit r1, bit r2, bit r3, bitr4, bit r5, bit r6, bit r7, bit r8, bit r9, bit r10, bit r11, bit r12,bit r13, bit r14, and bit r15 are arranged in order, and are located inthis order with respect to a frame, for example.

As another method, a bit sequence in which the order of “bit r1, bit r2,bit r3, bit r4, bit r5, bit r6, bit r7, bit r8, bit r9, bit r10, bitr11, bit r12, bit r13, bit r14, and bit r15” is changed, for example, abit sequence of “bit r7, bit r2, bit r4, bit r6, bit r13, bit r1, bitr8, bit r12, bit r9, bit r5, bit r10, bit r3, bit r15, bit r11, and bitr14” may be located in this order with respect to a frame. The order inthe bit sequence is not limited to this example.

In addition, in FIG. 84 , it is assumed that field s0, field s1, fields2, and field s3 exist as the “single-carrier scheme and OFDM schemerelated reception capability notification symbol 9401”. Also, it isassumed that field s4, field s5, field s6, and field s7 exist as the“single-carrier scheme related reception capability notification symbol9402”. Also, it is assumed that field s8, field s9, field s10, and fields11 exist as the “OFDM scheme related reception capability notificationsymbol 9403”. Also, it is assumed that field s12, field s13, field s14,and field s15 exist as the “other reception capability notificationsymbol 9801”. It is assumed that a “field” is made up of one or morebits.

In the case of FIG. 84 , it is assumed that field s1, field s2, fields3, field s4, field s5, field s6, field s7, field s8, field s9, fields10, field s11, field s12, field s13, field s14, and field s15 arearranged in order, and are located in this order with respect to aframe, for example.

As another method, a field sequence in which the order of “field s1,field s2, field s3, field s4, field s5, field s6, field s7, field s8,field s9, field s10, field s11, field s12, field s13, field s14, andfield s15” is changed, for example, a field sequence of “field s7, fields2, field s4, field s6, field s13, field s1, field s8, field s12, fields9, field s5, field s10, field s3, field s15, field s1l, and field s14”may be located in this order with respect to a frame. The order in thefield sequence is not limited to this example.

It is not always explicitly indicated that the information transmittedby the “single-carrier scheme related reception capability notificationsymbol” is information directed to the single-carrier scheme. Theinformation transmitted by the “single-carrier scheme related receptioncapability notification symbol” described in the present embodiment is,for example, information for giving a notice about a selectable schemein a case where the transmission apparatus transmits a signal in thesingle-carrier scheme. In another example, the information transmittedby the “single-carrier scheme related reception capability notificationsymbol” described in the present embodiment is, for example, informationthat is not used (ignored) to select a scheme to be used fortransmitting a signal in a case where the transmission apparatustransmits a signal in a scheme other than the single-carrier scheme,such as the OFDM scheme. In still another example, the informationtransmitted by the “single-carrier scheme related reception capabilitynotification symbol” described in the present embodiment is, forexample, information that is transmitted by using a region determined tobe an invalid region or reserved region by the transmission apparatus orthe reception apparatus in a case where the reception apparatus does notsupport the reception of a signal of the single-carrier scheme (notifiesthe transmission apparatus of non-support). In the above description,the term “single-carrier scheme related reception capabilitynotification symbol 9402” is used, but the term is not limited thereto,and another term may be used. For example, the term “symbol indicatingthe reception capability of the (first) terminal #p” may be used. Inaddition, the “single-carrier scheme related reception capabilitynotification symbol 9402” may include information other than informationfor giving a notice about a receivable signal.

Likewise, it is not always explicitly indicated that the informationtransmitted by the “OFDM scheme related reception capabilitynotification symbol” is information directed to the OFDM scheme. Theinformation transmitted by the “OFDM scheme related reception capabilitynotification symbol” described in the present embodiment is, forexample, information for giving a notice about a selectable scheme in acase where the transmission apparatus transmits a signal in the OFDMscheme. In another example, the information transmitted by the “OFDMscheme related reception capability notification symbol” described inthe present embodiment is, for example, information that is not used(ignored) to select a scheme to be used for transmitting a signal in acase where the transmission apparatus transmits a signal in a schemeother than the OFDM scheme, such as the single-carrier scheme. In stillanother example, the information transmitted by the “OFDM scheme relatedreception capability notification symbol” described in the presentembodiment is, for example, information that is transmitted by using aregion determined to be an invalid region or reserved region by thetransmission apparatus or the reception apparatus in a case where thereception apparatus does not support the reception of a signal of theOFDM scheme. In the above description, the term “OFDM scheme relatedreception capability notification symbol 9403” is used, but the term isnot limited thereto, and another term may be used. For example, the term“symbol indicating the reception capability of the (second) terminal #p”may be used. In addition, the “OFDM scheme related reception capabilitynotification symbol 9403” may include information other than informationfor giving a notice about a receivable signal.

The term “single-carrier scheme and OFDM scheme related receptioncapability notification symbol 9401” is used, but the term is notlimited thereto, and another term may be used. For example, the term“symbol indicating the reception capability of the (third) terminal #p”may be used. In addition, the “single-carrier scheme and OFDM schemerelated reception capability notification symbol 9401” may includeinformation other than information for giving a notice about areceivable signal.

As in the present embodiment, the terminal #p forms and transmits areception capability notification symbol, and the base station receivesthe reception capability notification symbol, generates a modulatedsignal by considering the effectiveness of the value thereof, andtransmits the modulated signal. Accordingly, the terminal #p is able toreceive the modulated signal that can be demodulated, and is thus ableto appropriately obtain data and improve the data reception quality. Inaddition, the terminal #p generates data of each bit (each field) of thereception capability notification symbol while determining theeffectiveness of the bit (the field), and is thus able to reliablytransmit the reception capability notification symbol to the basestation and improve the communication quality.

In the present embodiment, in a case where the base station or AP doesnot support the transmission of a modulated signal of the OFDMA scheme,the base station or AP does not transmit a modulated signal of the OFDMAscheme even if the terminal #p supports the demodulation of the OFDMAscheme.

Twenty-fifth Embodiment

In the present embodiment, a description will be given of another methodfor carrying out the operation of the terminal #p described in the thirdembodiment, the fifth embodiment, the fifteenth embodiment, thetwentieth embodiment, the twenty-first embodiment, the twenty-secondembodiment, the twenty-third embodiment, the twenty-fourth embodiment,and so forth.

FIG. 89 is a diagram illustrating an example of the format of areception capability notification symbol. The format of the receptioncapability notification symbol in FIG. 89 includes an ID symbol field8901, a Length symbol field 8902, a Core Capabilities field 8903, and NExtended Capabilities fields (Extended Capabilities 1 (8904_1) toExtended Capabilities N (8904_N)) (N is an integer equal to or greaterthan 1). An ID Extension symbol field may be included between the Lengthsymbol field 8902 and the Core Capabilities field 8903.

The ID symbol field 8901 has a length of 8 bits, the Length symbol field8902 has a length of 8 bits, the Core Capabilities field 8903 has alength of 32 bits, the Extended Capabilities 1 (8904_1) has a length ofX1 bits (X1 is an integer equal to or greater than 1), and the ExtendedCapabilities N (8904_N) has a length of XN bits (XN is an integer equalto or greater than 1). In a case where the format of the receptioncapability notification symbol includes an ID Extension symbol field,the ID Extension symbol field has a length of 8 bits.

FIG. 90 is a diagram illustrating an example of the format of theExtended Capabilities field in FIG. 89 . The Extended Capabilities fieldin FIG. 90 includes, as subfields, a Capabilities ID 10401, aCapabilities Length 10402, and a Capabilities Payload 10403. TheCapabilities ID 10401 has a length of 8 bits, the Capabilities Length10402 has a length of 8 bits, and the Capabilities Payload 10403 has alength of X bits (X is an integer equal to or greater than 1).

Each of the N Extended Capabilities fields (Extended Capabilities 1(8904_1) to Extended Capabilities N (8904_N)) illustrated in FIG. 89 (Nis an integer equal to or greater than 1) includes the fields(subfields) illustrated in FIG. 90 .

The terminal #p transmits not all the N Extended Capabilities fields(Extended Capabilities 1 (8904_1) to Extended Capabilities N (8904_N))(N is an integer equal to or greater than 1) to the base station (AP),but designates ID (identification) and Length (length) to transmit oneor more designated Extended Capabilities fields to the base station(AP). Note that it is possible that the terminal #p does not transmit anExtended Capabilities field.

For example, the terminal #p that does not support all Capabilities(reception capabilities) indicated by the Capabilities ID “2” need nottransmit the Extended Capabilities field having the Capabilities ID “2”to the base station (AP). However, the terminal #p may transmit theExtended Capabilities field having the Capabilities ID “2” to the basestation (AP).

First Example

For example, the Extended Capabilities field with a Capabilities ID 0(zero) includes the following.

FIG. 91 is a diagram illustrating a first example of the ExtendedCapabilities field. In the Extended Capabilities field in FIG. 91 , thedata 2801 about “support/not support demodulation of modulated signalwith phase change” and the data 2901 about “support/not supportreception for multiple streams” in FIG. 29 are transmitted with the sameCapabilities ID.

Accordingly, the terminal #p that does not support reception formultiple streams need not transmit the Extended Capabilities fieldillustrated in FIG. 91 , and thus the data transmission speed increases.This is because unnecessary resources can be allocated to the time fordata transmission.

In addition, the terminal #p that supports reception for multiplestreams transmits the “Extended Capabilities field” in FIG. 91 , therebybeing able to transmit information indicating whether or not phasechange demodulation is supported, together with information indicatingthat reception for multiple streams is supported. In this way,information about two types of reception capabilities can be transmittedby using a single “Extended Capabilities field”, and thus the datatransmission speed increases. On the other hand, in the case ofindividually transmitting the data 2801 about “support/not supportdemodulation of modulated signal with phase change” and the data 2901about “support/not support reception for multiple streams” by usingExtended Capabilities fields having Capabilities IDs different from eachother, the terminal #p needs to transmit multiple (two) ExtendedCapabilities fields corresponding to multiple Capabilities IDs, andaccordingly the data transmission speed decreases. The ExtendedCapabilities field in FIG. 91 may include another reception capabilitynotification symbol.

Second Example

For example, the “Extended Capabilities field” with a Capabilities ID 0(zero) includes the following.

FIG. 92 is a diagram illustrating a second example of the ExtendedCapabilities field. In the Extended Capabilities field in FIG. 92 , thedata 5301 about “supported precoding method” in FIG. 71 as well as thedata 2801 about “support/not support demodulation of modulated signalwith phase change” and the data 2901 about “support/not supportreception for multiple streams” in FIG. 29 are transmitted with the sameCapabilities ID.

Accordingly, the terminal #p that does not support reception formultiple streams need not transmit the “Extended Capabilities field”illustrated in FIG. 92 , and thus the data transmission speed increases.This is because unnecessary resources can be allocated to the time fordata transmission.

On the other hand, the terminal #p that supports reception for multiplestreams transmits the “Extended Capabilities field” in FIG. 92 includingthe data 5301 about “supported precoding method” in FIG. 71 as well asthe data 2801 about “support/not support demodulation of modulatedsignal with phase change” and the data 2901 about “support/not supportreception for multiple streams”. At this time, information about“support/not support demodulation of modulated signal with phase change”and information about “supported precoding methods” can be transmittedby using the single “Extended Capabilities field”, and thus the datatransmission speed increases. On the other hand, in the case oftransmitting the data 2801 about “support/not support demodulation ofmodulated signal with phase change” and the data 5301 about “supportedprecoding methods” by using an Extended Capabilities field having aCapabilities ID different from the Capabilities ID for transmitting thedata 2901 about “support/not support reception for multiple streams”, itis necessary to transmit multiple Extended Capabilities fieldscorresponding to multiple Capabilities IDs, and accordingly the datatransmission speed decreases. The Extended Capabilities field in FIG. 92may include another reception capability notification symbol.

Third Example

FIG. 93 is a diagram illustrating a third example of the ExtendedCapabilities field. In FIG. 93 , the data 9601 about “schemes supportedby single-carrier scheme” in FIG. 82 is transmitted by using an ExtendedCapabilities field 8904_k (k is an integer from 1 to N) having a firstCapabilities ID, and the data 9701 about “schemes supported by OFDMscheme” in FIGS. 83, 85, 86, 87, 88 , and so forth is transmitted byusing an Extended Capabilities field 8904_m (m is different from k andis an integer from 1 to N) having a second Capabilities ID. Note thatthe first Capabilities ID and the second Capabilities ID are differentfrom each other.

At this time, the terminal #p that supports transmission of a modulatedsignal of the single-carrier scheme and that does not supporttransmission of a modulated signal of the OFDM scheme does not need totransmit the Extended Capabilities field 8904_m having the secondCapabilities ID and for transmitting the data 9701 about “schemessupported by OFDM scheme”, and thus the data transmission speedincreases. However, the terminal #p may transmit the ExtendedCapabilities field 8904_m.

Likewise, the terminal #p that supports transmission of a modulatedsignal of the OFDM scheme and that does not support transmission of amodulated signal of the single-carrier scheme does not need to transmitthe Extended Capabilities field 8904_k having the first Capabilities IDand for transmitting the data 9601 about “schemes supported by thesingle-carrier scheme”, and thus the data transmission speed increases.However, the terminal #p may transmit the Extended Capabilities field8904_k.

Furthermore, it is assumed that the data 5301 about “supported precodingmethods”, the data 2801 about “support/not support demodulation ofmodulated signal with phase change”, and the data 2901 about“support/not support reception for multiple streams” illustrated in FIG.71 and so forth are transmitted by using the “Extended Capabilitiesfield” having the same Capability ID.

Accordingly, the terminal #p that supports the OFDM scheme and that doesnot support reception for multiple streams does not need to transmitthis Extended Capabilities field, and thus the data transmission speedincreases. This is because unnecessary resources can be allocated to thetime for data transmission.

In addition, the terminal #p that supports the OFDM scheme and thatsupports reception for multiple streams transmits this ExtendedCapabilities field. At this time, the terminal #p is able to transmitinformation indicating whether or not phase change demodulation issupported and information about supported precoding methods by using asingle “Extended Capabilities field”, and thus the data transmissionspeed increases. The reason for this is as described above.

Fourth Example

FIG. 94 is a diagram illustrating a fourth example of the ExtendedCapabilities field. In FIG. 94 , the data 9601 about “schemes supportedby single-carrier scheme” in FIG. 82 is transmitted by using theExtended Capabilities field 8904_k (k is an integer from 1 to N) havingthe first Capabilities ID, the data 9701 about “schemes supported byOFDM scheme” in FIGS. 83, 85, 86, 87, 88 , and so forth is transmittedby using the Extended Capabilities field 8904_m (m is different from kand is an integer from 1 to N) having the second Capabilities ID, andthe “single-carrier scheme and OFDM scheme related reception capabilitynotification symbol 9401” in FIG. 80 is transmitted by using an ExtendedCapabilities field 8904_n (n is different from k and m and is an integerfrom 1 to N) having a third Capabilities ID. Note that the firstCapabilities ID and the second Capabilities ID are different from eachother, the first Capabilities ID and the third Capabilities ID aredifferent from each other, and the second Capabilities ID and the thirdCapabilities ID are different from each other.

At this time, the terminal #p that supports transmission of a modulatedsignal of the single-carrier scheme and that does not supporttransmission of a modulated signal of the OFDM scheme does not need totransmit the Extended Capabilities field 8904_m having the secondCapabilities ID and for transmitting the data 9701 about “schemessupported by OFDM scheme”, and thus the data transmission speedincreases. This is because unnecessary resources can be allocated to thetime for data transmission. However, the terminal #p may transmit theExtended Capabilities field 8904_m.

Fifth Example

FIG. 95 is a diagram illustrating a fifth example of the ExtendedCapabilities field. In FIG. 95 , a symbol 10501 about “support/notsupport reception for multiple streams in single-carrier scheme” istransmitted by using the Extended Capabilities field 8904_k (k is aninteger from 1 to N) having the first Capabilities ID, and a symbol10601 about “support/not support reception for multiple streams in OFDMscheme” is transmitted by using the Extended Capabilities field 8904_m(m is different from k and is an integer from 1 to N) having the secondCapabilities ID. Note that the first Capabilities ID and the secondCapabilities ID are different from each other. The symbol 10501 about“support/not support reception for multiple streams in single-carrierscheme” is a symbol for transmitting information about “support/notsupport reception for multiple streams in single-carrier scheme”. Thesymbol 10601 about “support/not support reception for multiple streamsin OFDM scheme” is a symbol for transmitting information about“support/not support reception for multiple streams in OFDM scheme”.

At this time, the terminal #p that does not support reception formultiple streams in the single-carrier scheme does not need to transmitthe Extended Capabilities field 8904_k having the first Capabilities ID,and thus the data transmission speed increases. This is becauseunnecessary resources can be allocated to the time for datatransmission.

Likewise, the terminal #p that does not support reception for multiplestreams in the OFDM scheme does not need to transmit the ExtendedCapabilities field 8904_m having the second Capabilities ID, and thusthe data transmission speed increases. In the above-described first tofourth examples, the effects similar to those described above can beobtained.

Sixth Example

As a modification example of the above-described fifth example, symbolsfor transmitting the data 9701 about “schemes supported by OFDM scheme”in FIG. 96 are transmitted by using the Extended Capabilities fieldhaving the first Capabilities ID, and data 10801 about “schemessupported by single-carrier scheme” in FIG. 97 is transmitted by usingthe Extended Capabilities field having the second Capabilities ID. Notethat the first Capabilities ID and the second Capabilities ID aredifferent from each other.

As illustrated in FIG. 96 , the data 9701 about “schemes supported byOFDM scheme” includes the symbol 10601 about “support/not supportreception for multiple streams in OFDM scheme”, the data 5301 about“supported precoding methods”, and the data 2801 about “support/notsupport demodulation of modulated signal with phase change”.Accordingly, the effects described in the first example and the secondexample can be obtained.

In addition, as illustrated in FIG. 97 , the data 10801 about “schemessupported by single-carrier scheme” includes the symbol 10501 about“support/not support reception for multiple streams in single-carrierscheme”. Accordingly, the effects similar to those described in thefifth example can be obtained.

Seventh Example

It is assumed that the symbol 10601 about “support/not support receptionfor multiple streams in OFDM scheme”, the data 5301 about “supportedprecoding methods”, and the data 2801 about “support/not supportdemodulation of modulated signal with phase change” included in the data9701 about “schemes supported by OFDM scheme” in FIG. 96 , and thesymbol 10501 about “support/not support reception for multiple streamsin single-carrier scheme” included in the data 10801 about “schemessupported by single-carrier scheme” in FIG. 97 are transmitted by usingthe Extended Capabilities field having the first Capabilities ID.

Accordingly, it is sufficient that the terminal #p that supportsreception of multiple streams transmit the Extended Capabilities fieldhaving a single Capabilities ID, and thus the number of ExtendedCapabilities fields having other Capabilities IDs to be transmitted canbe reduced. Thus, the data transmission speed can be increasedadvantageously. In the seventh example, in a case where “reception formultiple streams in the OFDM scheme is supported and reception formultiple streams in the single-carrier scheme is supported”, and in acase where “reception for multiple streams in the OFDM scheme is notsupported and reception for multiple streams in the single-carrierscheme is not supported”, it is not necessary to separate the symbol10601 about “support/not support reception for multiple streams in OFDMscheme” and the symbol 10501 about “support/not support reception formultiple streams in single-carrier scheme”. Thus, in these cases, it isonly necessary to transmit a symbol about “support/not support receptionfor multiple streams” by using the Extended Capabilities field havingthe first Capabilities ID.

Eighth Example

The “single-carrier scheme and OFDM scheme related reception capabilitynotification symbol 9401” illustrated in FIG. 80 and so forth may betransmitted by using a Core Capabilities field (for example, the CoreCapabilities field 8903 illustrated in FIG. 89 ), and the “OFDM schemerelated reception capability notification symbol 9403” illustrated inFIG. 80 and so forth may be transmitted by using an ExtendedCapabilities field (for example, at least any one of ExtendedCapabilities 1 (8904_1) to Extended Capabilities N (8904_N) in FIG. 89).

Ninth Example

When the base station (AP) transmits modulated signals includingmultiple streams in the OFDMA scheme to the terminal #p by usingmultiple antennas, a symbol indicating whether or not the terminal #p isable to demodulate these modulated signals is data 10901 about“support/not support reception for multiple streams in OFDMA scheme” inFIG. 98 . In the OFDMA scheme, the data 10901 about “support/not supportreception for multiple streams in OFDMA scheme” is data (for example,symbol) for transmitting information about “support/not supportreception for multiple streams in OFDMA scheme”. On the basis of thedata 10901 about “support/not support reception for multiple streams inOFDMA scheme” transmitted from the terminal #p, the base station (AP)determines whether or not to transmit modulated signals of multiplestreams. This method is as described in another embodiment. Accordingly,the base station (AP) is able to transmit a modulated signal that can bedemodulated by the terminal #p.

In addition, as in FIG. 99 , the terminal #p transmits the data 10302about “support/not support demodulation of OFDMA scheme” and the data10901 about “support/not support reception for multiple streams in OFDMAscheme” by using the Extended Capabilities field having the first (same)Capabilities ID.

Accordingly, the terminal #p that supports reception for multiplestreams in the OFDMA scheme transmits the Extended Capabilities fieldhaving the first Capabilities ID. On the basis of the ExtendedCapabilities field having the first Capabilities ID received from theterminal #p, the base station (AP) is able to determine whether or notto transmit modulated signals of multiple streams in the OFDMA scheme.In this method, it is not necessary to transmit Extended Capabilitiesfields having other Capabilities IDs, and thus an effect that the datatransmission speed increases can be obtained.

In addition, the terminal #p transmits, to the base station (AP), anytwo or more of the symbol 10501 about “support/not support reception formultiple streams in single-carrier scheme” in FIG. 100 and the symbol10601 about “support/not support reception for multiple streams in OFDMscheme” in FIG. 101 , and the data 10901 about “support/not supportreception for multiple streams in OFDMA scheme” in FIG. 98 , andaccordingly the base station (AP) is able to transmit a modulated signalin an appropriate scheme. Thus, an effect that the data transmissionspeed increases can be obtained.

Preferably, the terminal #p may transmit, by using the ExtendedCapabilities field, any two or more of the symbol 10501 about“support/not support reception for multiple streams in single-carrierscheme” in FIG. 100 and the symbol 10601 about “support/not supportreception for multiple streams in OFDM scheme” in FIG. 101 , and thedata 10901 about “support/not support reception for multiple streams inOFDMA scheme” in FIG. 98 . Accordingly, there is a possibility that theterminal #p that does not support demodulation of multiple streams isable to reduce the number of Extended Capabilities fields to betransmitted, and thus the data transmission speed increases.

Tenth Example

The terminal #p transmits at least two or more symbols among the data2801 about “support/not support demodulation of modulated signal withphase change”, the data 2901 about “support/not support reception formultiple streams”, the data 3001 about “supported schemes, the data 3002about “support/not support multi-carrier scheme”, the data 3003 about“supported error-correcting coding schemes”, and the data 5301 about“supported precoding methods” illustrated in FIGS. 30 and 71 , by usingthe Extended Capabilities field having the first Capabilities ID.

Accordingly, when the terminal #p transmits a reception capabilitynotification symbol related to a physical layer by using ExtendedCapabilities fields, the number of Extended Capabilities fields to betransmitted can be reduced. Accordingly, the data transmission speed canbe increased. This is because saved resources can be allocated to thetime for data transmission.

Obviously, it is possible to carry out the present embodiment and “thetwentieth to twenty-fourth embodiments” in combination with each other.At this time, it is obviously possible to implement the receptioncapability notification symbol, the configuration of individualparameters constituting the reception capability notification symbol,and the usage method therefor described in the present embodiment in themanner described in the twentieth to twenty-fourth embodiments. Inaddition, a combination with another embodiment is obviously possible.

Supplemental Description

A description has been given above of a symbol for transmittinginformation indicating “support/not support reception for multiplestreams” (for example, 2901), a symbol for transmitting informationindicating “support/not support reception for multiple streams insingle-carrier scheme” (for example, 10501), and a symbol fortransmitting information indicating “support/not support reception formultiple streams in OFDM scheme” (for example, 10601). At this time, thefollowing three methods are conceivable as a method for transmittinginformation indicating “support/not support reception for multiplestreams”, for example.

First Method:

Information indicating whether or not reception for multiple streams issupported is transmitted. For example, “1” is transmitted in a casewhere the terminal #p supports reception for multiple streams, and “0”is transmitted in a case where the terminal #p does not supportreception for multiple streams.

Second Method:

The symbol for transmitting information indicating “support/not supportreception for multiple streams” (for example, 2901, 10501, 10601, or thelike) is made up of a symbol for transmitting information indicating“the number of receivable streams” or a symbol for transmittinginformation indicating “the maximum number of receivable streams”.

Third Method:

The terminal #p transmits information indicating “whether or notreception for multiple streams is supported” as described in the firstmethod, and transmits a symbol for transmitting information indicating“the number of receivable streams” or a symbol for transmittinginformation indicating “the maximum number of receivable streams” asdescribed in the second method.

Now, a description will be given of a case where the symbol fortransmitting information indicating “support/not support reception formultiple streams” is made up of a symbol for transmitting informationindicating “the number of receivable streams” or a symbol fortransmitting information indicating “the maximum number of receivablestreams” in the second method described above.

For example, a modulated signal obtained by modulating a first datasequence (performing mapping in a certain modulation scheme) by the basestation (AP) is represented by s1(i) (i is a symbol number), a modulatedsignal obtained by modulating a second data sequence (performing mappingin a certain modulation scheme) by the base station (AP) is representedby s2(i), a modulated signal obtained by modulating a third datasequence (performing mapping in a certain modulation scheme) by the basestation (AP) is represented by s3(i), and a modulated signal obtained bymodulating a fourth data sequence (performing mapping in a certainmodulation scheme) by the base station (AP) is represented by s4(i).

Also, it is assumed that the base station (AP) supports some of thefollowing transmissions.

<1> Transmission of the modulated signal (stream) of s1(i).<2> Transmission of the modulated signal (stream) of s1(i) and themodulated signal (stream) of s2(i) at identical times and identicalfrequencies with use of multiple antennas. The base station (AP) may ormay not perform precoding.<3> Transmission of the modulated signal (stream) of s1(i), themodulated signal (stream) of s2(i), and the modulated signal (stream) ofs3(i) at identical times and identical frequencies with use of multipleantennas. The base station (AP) may or may not perform precoding.<4> Transmission of the modulated signal (stream) of s1(i), themodulated signal (stream) of s2(i), the modulated signal (stream) ofs3(i), and the modulated signal (stream) of s4(i) at identical times andidentical frequencies with use of multiple antennas. The base station(AP) may or may not perform precoding.

For example, it is assumed that the terminal #p is able to performdemodulation in the above-described cases <1> and <2>. At this time, themaximum number of streams that can be demodulated by the terminal #p is2, and thus the terminal #p transmits information “2” by using thesymbol for transmitting information indicating “the number of receivablestreams” or the symbol for transmitting information indicating “themaximum number of receivable streams”.

For another example, it is assumed that the terminal #p is able toperform demodulation in all the above-described cases <1>, <2>, <3>, and<4>. At this time, the maximum number of streams that can be demodulatedby the terminal #p is 4, and thus the terminal #p transmits information“4” by using the symbol for transmitting information indicating “thenumber of receivable streams” or the symbol for transmitting informationindicating “the maximum number of receivable streams”.

For still another example, it is assumed that the terminal #p is able toperform demodulation only in the case <1>. At this time, the maximumnumber of streams that can be demodulated by the terminal #p is 1, andthus the terminal #p transmits information “1” by using the symbol fortransmitting information indicating “the number of receivable streams”or the symbol for transmitting information indicating “the maximumnumber of receivable streams”.

For another example, it is assumed that the terminal #p is able toperform demodulation only in the case <2>. At this time, the maximumnumber of streams that can be demodulated by the terminal #p is 2, andthus the terminal #p transmits information “2” by using the symbol fortransmitting information indicating “the number of receivable streams”or the symbol for transmitting information indicating “the maximumnumber of receivable streams”.

For another example, it is assumed that the terminal #p is able toperform demodulation in the cases <3> and <4>. At this time, the maximumnumber of streams that can be demodulated by the terminal #p is 4, andthus the terminal #p transmits information “4” by using the symbol fortransmitting information indicating “the number of receivable streams”or the symbol for transmitting information indicating “the maximumnumber of receivable streams”.

For another example, it is assumed that the terminal #p is able toperform demodulation in the case <4>. At this time, the maximum numberof streams that can be demodulated by the terminal #p is 4, and thus theterminal #p transmits information “4” by using the symbol fortransmitting information indicating “the number of receivable streams”or the symbol for transmitting information indicating “the maximumnumber of receivable streams”.

For another example, it is assumed that the terminal #p is able toperform demodulation in the cases <1> and <4>. At this time, the maximumnumber of streams that can be demodulated by the terminal #p is 4, andthus the terminal #p transmits information “4” by using the symbol fortransmitting information indicating “the number of receivable streams”or the symbol for transmitting information indicating “the maximumnumber of receivable streams”.

For another example, it is assumed that the terminal #p is able toperform demodulation in the cases <1> and <2>. At this time, the numberof streams that can be demodulated by the terminal #p is 1 and 2, andthus the terminal #p transmits information “1 and 2” by using the symbolfor transmitting information indicating “the number of receivablestreams”.

For another example, it is assumed that the terminal #p is able toperform demodulation in the cases <1>, <2>, <3>, and <4>. At this time,the number of streams that can be demodulated by the terminal #p is 1,2, 3, and 4, and thus the terminal #p transmits information “1 and 2 and3 and 4” by using the symbol for transmitting information indicating“the number of receivable streams”.

For another example, it is assumed that the terminal #p is able toperform demodulation in the case <1>. At this time, the number ofstreams that can be demodulated by the terminal #p is 1, and thus theterminal #p transmits information “1” by using the symbol fortransmitting information indicating “the number of receivable streams”.

For another example, it is assumed that the terminal #p is able toperform demodulation in the case <2>. At this time, the number ofstreams that can be demodulated by the terminal #p is 2, and thus theterminal #p transmits information “2” by using the symbol fortransmitting information indicating “the number of receivable streams”.

For another example, it is assumed that the terminal #p is able toperform demodulation in the cases <3> and <4>. At this time, the numberof streams that can be demodulated by the terminal #p is 3 and 4, andthus the terminal #p transmits information “3 and 4” by using the symbolfor transmitting information indicating “the number of receivablestreams”.

For another example, it is assumed that the terminal #p is able toperform demodulation in the case <4>. At this time, the number ofstreams that can be demodulated by the terminal #p is 4, and thus theterminal #p transmits information “4” by using the symbol fortransmitting information indicating “the number of receivable streams”.

For another example, it is assumed that the terminal #p is able toperform demodulation in the cases <1> and <4>. At this time, the numberof streams that can be demodulated by the terminal #p is 1 and 4, andthus the terminal #p transmits information “1 and 4” by using the symbolfor transmitting information indicating “the number of receivablestreams”.

For another example, it is assumed that the terminal #p is able toperform demodulation in the cases <1>, <2>, and <4>. At this time, thenumber of streams that can be demodulated by the terminal #p is 1, 2,and 4, and thus the terminal #p transmits information “1, 2, and 4” byusing the symbol for transmitting information indicating “the number ofreceivable streams”.

The “reception capability notification symbol” has been mainly describedabove, but the terminal #p may transmit a “transmission capabilitynotification symbol” in addition to the “reception capabilitynotification symbol”. In a case where the terminal #p transmits the“transmission capability notification symbol”, the operation may becarried out similarly to the case of transmitting the “receptioncapability notification symbol”.

An example of the “transmission capability notification symbol” will bedescribed. The terminal #p may transmit, to the base station (AP), the“transmission capability notification symbol” that includes informationindicating “support/not support MIMO transmission”, informationindicating “the number of transmittable streams”, information indicating“the maximum number of transmittable streams”, or information indicating“support/not support transmission of multiple streams”. Accordingly, thebase station (AP) is able to transmit, to the terminal #p, a request fora modulated signal transmitted from the terminal #p. Here, the streamsmean streams that are different from each other.

The information indicating “the number of transmittable streams” and theinformation indicating “the maximum number of transmittable streams” asdescribed above may be transmitted by using the “Extended Capabilitiesfield” or the “Core Capabilities field”, similarly to the case of the“reception capability notification symbol” described above.

In addition, both the “reception capability notification symbol” and the“transmission capability notification symbol” for the same terminal maybe transmitted by including them in a single capability element formator in different capability element formats. Furthermore, the “receptioncapability notification symbol” and the “transmission capabilitynotification symbol” may be correctively referred to as a “transmissionand reception capabilities notification symbol”.

Twenty-sixth Embodiment

In embodiments such as the first embodiment, the second embodiment, andthe third embodiment, a description has been given of configurationsincluding the weight combiner 303, the phase changer 305A, and/or thephase changer 305B in FIGS. 3, 4, 26, 40, 41, 42, 43, 44, 45, 46, 47,and 48 , for example. Hereinafter, a description will be given of aconfiguration method for obtaining favorable reception quality in anembodiment in which direct waves are dominant or an environment in whicha multipath or the like exists.

First, a description will be given of a phase change method in a casewhere the weight combiner 303 and the phase changer 305B exist, as inFIGS. 3, 4, 41, 45, 47 , and so forth.

For example, as described in the above-described embodiments, it isassumed that the phase change value in the phase changer 305B is givenas yp(i). Here, i is a symbol number, and i is an integer equal to orgreater than 0, for example.

For example, supposing that the phase change value yp(i) is the periodof N, N values are prepared as the phase change value. Here, N is aninteger equal to or greater than 2. For example, Phase[0], Phase[1],Phase[2], Phase[3], . . . , Phase[N-2], and Phase[N-1] are prepared asthe N values. That is, Phase[k] is prepared, where k is an integer from0 to N-1. Also, Phase[k] is a real number from 0 radians to 2π radians.In addition, u is an integer from 0 to N-1, v is an integer from 0 toN-1, and u≠v holds. In all u and v satisfying these conditions,Phase[u]≠Phase[v] holds. The method for setting the phase change valueyp(i) when the period is supposed to be N is as described in anotherembodiment in this specification. M values are extracted from Phase[0],Phase[1], Phase[2], Phase[3], . . . , Phase[N-2], and Phase[N-1], andthese M values are expressed as Phase_1 [0], Phase_1 [1], Phase_1 [2], .. . , Phase_1[M-2], and Phase_1[M-1]. That is, Phase_1[k] is given,where k is an integer from 0 to M-1. Here, M is an integer smaller thanN and equal to or greater than 2.

At this time, it is assumed that the phase change value yp(i) takes anyvalue from among Phase_1 [0], Phase_1 [1], Phase_1 [2], . . . ,Phase_1[M-2], and Phase_1[M-1]. Also, it is assumed that each of Phase_1[0], Phase_1 [1], Phase_1 [2], . . . , Phase_1[M-2], and Phase_1[M-1] isused as the phase change value yp(i) at least once.

For example, as one example thereof, there is a method in which theperiod of the phase change value yp(i) is M. At this time, the followingexpression holds.

yp(i=u+v×M)=Phase_1[u]  Expression (75)

Here, u is an integer from 0 to M-1. Also, v is an integer equal to orgreater than 0.

In addition, weight combining processing and phase change processing maybe respectively performed by the weight combiner 303 and the phasechanger 305B as in FIG. 3 and so forth, or the processing by the weightcombiner 303 and the processing by the phase changer 305B may beperformed by a first signal processor 6200 as in FIG. 102 . In FIG. 102, the elements that operate similarly to those in FIG. 3 are denoted bythe same numerals.

For example, in Expression (3), when the matrix for weight combining isrepresented by Fp and the matrix related to phase change is representedby Pp, a matrix Wp (=Pp×Fp) is prepared in advance. In addition, thefirst signal processor 6200 in FIG. 102 may generate the signals 304Aand 306B by using the matrix Wp, the signal 301A (sp1(t)), and thesignal 301B (sp2(t)).

The phase changers 309A, 309B, 3801A, and 3801B in FIGS. 3, 4, 41, 45,and 47 may or may not perform signal processing for phase change.

As a result of setting the phase change value yp(i) in the foregoingmanner, it is possible to obtain an effect of an increased possibilitythat the reception apparatus is able to obtain favorable receptionquality due to the spatial diversity effect in an environment in whichdirect waves are dominant or an environment in which a multipath or thelike exists. Furthermore, as a result of reducing the number of valuesthat can be taken as the phase change value yp(i) and reducing thenumber of values that can be taken as the phase change value w(i) asdescribed above, the possibility of decreasing the circuit scales of thetransmission apparatus and the reception apparatus is increased with theinfluence on the data reception quality being decreased.

Next, a description will be given of a phase change method in a casewhere the weight combiner 303, the phase changer 305A, and the phasechanger 305B exist, as in FIGS. 26, 40, 43, 44 , and so forth.

As described in another embodiment, it is assumed that the phase changevalue in the phase changer 305B is given as yp(i). Here, i is a symbolnumber, and i is an integer equal to or greater than 0, for example.

For example, supposing that the phase change value yp(i) is the periodof Nb, Nb values are prepared as the phase change value. Here, Nb is aninteger equal to or greater than 2. For example, Phase_b[0], Phase_b[1],Phase_b[2], Phase_b[3], . . . , Phase_b[Nb-2], and Phase_b[Nb-1] areprepared as the Nb values. That is, Phase_b[k] is prepared, where k isan integer from 0 to Nb-1. Also, Phase_b[k] is a real number from 0radians to 2π radians. In addition, u is an integer from 0 to Nb-1, v isan integer from 0 to Nb-1, and u≠v holds. In all u and v satisfyingthese conditions, Phase_b[u]≠Phase_b[v] holds. The method for settingthe phase change value yp(i) when the period is supposed to be Nb is asdescribed in another embodiment in this specification. Mb values areextracted from Phase_b[0], Phase_b[1], Phase_b[2], Phase_b[3], . . . ,Phase_b[Nb-2], and Phase_b[Nb-1], and these Mb values are expressed asPhase_1 [0], Phase_1 [1], Phase_1 [2], . . . , Phase_1[Mb-2], andPhase_1[Mb-1]. That is, Phase_1[k] is given, where k is an integer from0 to Mb-1. Here, Mb is an integer smaller than Nb and equal to orgreater than 2.

At this time, it is assumed that the phase change value yp(i) takes anyvalue from among Phase_1 [0], Phase_1 [1], Phase_1 [2], . . . ,Phase_1[Mb-2], and Phase_1[Mb-1]. Also, it is assumed that each ofPhase_1 [0], Phase_1 [1], Phase_1 [2], . . . , Phase_1[Mb-2], andPhase_1[Mb-1] is used as the phase change value yp(i) at least once.

For example, as one example thereof, there is a method in which theperiod of the phase change value yp(i) is Mb. At this time, thefollowing expression holds.

yp(i=u+v×Mb)=Phase_1[u]  Expression (76)

Here, u is an integer from 0 to Mb-1. Also, v is an integer equal to orgreater than 0.

As described in another embodiment, it is assumed that the phase changevalue in the phase changer 305A is given as Yp(i). Here, i is a symbolnumber, and i is an integer equal to or greater than 0, for example. Forexample, supposing that the phase change value Yp(i) is the period ofNa, Na values are prepared as the phase change value. Here, Na is aninteger equal to or greater than 2. For example, Phase_a[0], Phase_a[1],Phase_a[2], Phase_a[3], . . . , Phase_a[Na-2], and Phase_a[Na-1] areprepared as the Na values. That is, Phase_a[k] is prepared, where k isan integer from 0 to Na-1. Also, Phase_a[k] is a real number from 0radians to 2π radians. In addition, u is an integer from 0 to Na-1, v isan integer from 0 to Na-1, and u≠v holds. In all u and v satisfyingthese conditions, Phase_a[u]≠Phase_a[v] holds. The method for settingthe phase change value Yp(i) when the period is supposed to be Na is asdescribed in another embodiment in this specification. Ma values areextracted from Phase_a[0], Phase_a[1], Phase_a[2], Phase_a[3], . . . ,Phase_a[Na-2], and Phase_a[Na-1], and these Ma values are expressed asPhase_2 [0], Phase_2 [1], Phase_2 [2], . . . , Phase_2[Ma-2], andPhase_2[Ma-1]. That is, Phase_2[k] is given, where k is an integer from0 to Ma-1. Here, Ma is an integer smaller than Na and equal to orgreater than 2.

At this time, it is assumed that the phase change value Yp(i) takes anyvalue from among Phase_2 [0], Phase_2 [1], Phase_2 [2], . . . ,Phase_2[Ma-2], and Phase_2[Ma-1]. Also, it is assumed that each ofPhase_2 [0], Phase_2 [1], Phase_2 [2], . . . , Phase_2[Ma-2], andPhase_2[Ma-1] is used as the phase change value Yp(i) at least once.

For example, as one example thereof, there is a method in which theperiod of the phase change value Yp(i) is Ma. At this time, thefollowing expression holds.

Yp(i=u+v×Ma)=Phase_2[u]  Expression (77)

Here, u is an integer from 0 to Ma-1. Also, v is an integer equal to orgreater than 0.

In addition, weight combining processing and phase change processing maybe respectively performed by the weight combiner 303 and the phasechangers 305A and 305B as in FIGS. 26, 40, 43, 44 , and so forth, or theprocessing by the weight combiner 303 and the processing by the phasechangers 305A and 305B may be performed by a second signal processor6300 as in FIG. 103 . In FIG. 103 , the elements that operate similarlyto those in FIGS. 26, 40, 43, and 44 are denoted by the same numerals.

For example, in Expression (42), when the matrix for weight combining isrepresented by Fp and the matrix related to phase change is representedby Pp, a matrix Wp(=Pp×Fp) is prepared in advance. In addition, thesecond signal processor 6300 in FIG. 103 may generate the signals 306Aand 306B by using the matrix Wp, the signal 301A (sp1(t)), and thesignal 301B (sp2(t)).

The phase changers 309A, 309B, 3801A, and 3801B in FIGS. 26, 40, 43, and44 may or may not perform signal processing for phase change.

In addition, Na and Nb may be identical values or different values.Also, Ma and Mb may be identical values or different values.

As a result of setting the phase change value yp(i) and the phase changevalue Yp(i) in the foregoing manner, it is possible to obtain an effectof an increased possibility that the reception apparatus is able toobtain favorable reception quality due to the spatial diversity effectin an environment in which direct waves are dominant or an environmentin which a multipath or the like exists. Furthermore, as a result ofreducing the number of values that can be taken as the phase changevalue yp(i) or reducing the number of values that can be taken as thephase change value Yp(i) as described above, the possibility ofdecreasing the circuit scales of the transmission apparatus and thereception apparatus is increased with the influence on the datareception quality being decreased.

The present embodiment is highly likely to be effective when beingapplied to the phase change method described in another embodiment inthis specification. However, even when being applied to another phasechange method, the present embodiment can be carried out similarly.

Twenty-seventh Embodiment

In the present embodiment, a description will be given of a phase changemethod in a case where the weight combiner 303 and the phase changer305B exist, as in FIGS. 3, 4, 41, 45, 47 , and so forth.

For example, as described in the embodiments, it is assumed that thephase change value in the phase changer 305B is given as yp(i). Here, iis a symbol number, and i is an integer equal to or greater than 0, forexample.

For example, it is assumed that the phase change value yp(i) is theperiod of N. Here, N is an integer equal to or greater than 2. Phase[0],Phase[1], Phase[2], Phase[3], . . . , Phase[N-2], and Phase[N-1] areprepared as the N values. That is, Phase[k] is prepared, where k is aninteger from 0 to N-1. Also, Phase[k] is a real number from 0 radians to2π radians. In addition, u is an integer from 0 to N-1, v is an integerfrom 0 to N-1, and u≠v holds. In all u and v satisfying theseconditions, Phase[u]≠Phase[v] holds. At this time, Phase[k] is expressedby the following expression. Here, k is an integer from 0 to N-1.

$\begin{matrix}{{{Phase}\lbrack k\rbrack} = \frac{k\pi}{N}} & {{Expression}(78)}\end{matrix}$

Note that the unit of Expression (78) is the radian. In addition,Phase[0], Phase[1], Phase[2], Phase[3], . . . , Phase[N-2], andPhase[N-1] are used to allow the period of the phase change value yp(i)to be N. To obtain the period N, Phase[0], Phase[1], Phase[2], Phase[3],. . . , Phase[N-2], and Phase[N-1] may be arranged in any manner. Toobtain the period N, the following holds, for example.

yp(i=u+v×N)=yp(i=u+(v+1)×N)  Expression (79)

Here, u is an integer from 0 to N-1, and v is an integer equal to orgreater than 0. With all u and v satisfying these conditions, Expression(79) holds.

In addition, weight combining processing and phase change processing maybe respectively performed by the weight combiner 303 and the phasechanger 305B as in FIG. 3 and so forth, or the processing by the weightcombiner 303 and the processing by the phase changer 305B may beperformed by the first signal processor 6200 as in FIG. 102 . In FIG.102 , the elements that operate similarly to those in FIG. 3 are denotedby the same numerals.

For example, in Expression (3), when the matrix for weight combining isrepresented by Fp and the matrix related to phase change is representedby Pp, a matrix Wp (=Pp×Fp) is prepared in advance. In addition, thefirst signal processor 6200 in FIG. 102 may generate the signals 304Aand 306B by using the matrix Wp, the signal 301A (sp1(t)), and thesignal 301B (sp2(t)).

The phase changers 309A, 309B, 3801A, and 3801B in FIGS. 3, 4, 41, 45,and 47 may or may not perform signal processing for phase change.

As a result of setting the phase change value yp(i) in the foregoingmanner, it is possible to obtain an effect of an increased possibilitythat the reception apparatus is able to obtain favorable receptionquality due to the spatial diversity effect in an environment in whichdirect waves are dominant or an environment in which a multipath or thelike exists. Furthermore, as a result of limiting the number of valuesthat can be taken as the phase change value yp(i) as described above,the possibility of decreasing the circuit scales of the transmissionapparatus and the reception apparatus is increased with the influence onthe data reception quality being decreased.

Next, a description will be given of a phase change method in a casewhere the weight combiner 303, the phase changer 305A, and the phasechanger 305B exist, as in FIGS. 26, 40, 43, 44 , and so forth.

As described in another embodiment, it is assumed that the phase changevalue in the phase changer 305B is given as yp(i). Here, i is a symbolnumber, and i is an integer equal to or greater than 0, for example.

For example, it is assumed that the phase change value yp(i) is theperiod of Nb. Here, Nb is an integer equal to or greater than 2.Phase_b[0], Phase_b[1], Phase_b[2], Phase_b[3], . . . , Phase_b[Nb-2],and Phase_b[Nb-1] are prepared as the Nb values. That is, Phase_b[k] isprepared, where k is an integer from 0 to Nb-1. Also, Phase_b[k] is areal number from 0 radians to 2π radians. In addition, u is an integerfrom 0 to Nb-1, v is an integer from 0 to Nb-1, and u≠v holds. In all uand v satisfying these conditions, Phase_b[u]≠Phase_b[v] holds. At thistime, Phase_b[k] is expressed by the following expression. Here, k is aninteger from 0 to Nb-1.

$\begin{matrix}{{{Phase\_ b}\lbrack k\rbrack} = \frac{k\pi}{Nb}} & {{Expression}(80)}\end{matrix}$

Note that the unit of Expression (80) is the radian. In addition,Phase_b[0], Phase_b[1], Phase_b[2], Phase_b[3], . . . , Phase_b[Nb-2],and Phase_b[Nb-1] are used to allow the period of the phase change valueyp(i) to be Nb. To obtain the period Nb, Phase_b[0], Phase_b[1],Phase_b[2], Phase_b[3], . . . , Phase_b[Nb-2], and Phase_b[Nb-1] may bearranged in any manner. To obtain the period Nb, the following holds,for example.

yp(i=u+v×Nb)=yp(i=u+(v+1)×Nb)  Expression (81)

Here, u is an integer from 0 to Nb-1, and v is an integer equal to orgreater than 0. With all u and v satisfying these conditions, Expression(81) holds.

As described in another embodiment, it is assumed that the phase changevalue in the phase changer 305A is given as Yp(i). Here, i is a symbolnumber, and i is an integer equal to or greater than 0, for example. Forexample, it is assumed that the phase change value Yp(i) is the periodof Na. Here, Na is an integer equal to or greater than 2. Phase_a[0],Phase_a[1], Phase_a[2], Phase_a[3], . . . , Phase_a[Na-2], andPhase_a[Na-1] are prepared as the Na values. That is, Phase_a[k] isprepared, where k is an integer from 0 to Na-1. Also, Phase_a[k] is areal number from 0 radians to 2π radians. In addition, u is an integerfrom 0 to Na-1, v is an integer from 0 to Na-1, and u≠v holds. In all uand v satisfying these conditions, Phase_a[u]≠Phase_a[v] holds. At thistime, Phase_a[k] is expressed by the following expression. Here, k is aninteger from 0 to Na-1.

$\begin{matrix}{{{Phase\_ a}\lbrack k\rbrack} = \frac{k\pi}{Na}} & {{Expression}(82)}\end{matrix}$

Note that the unit of Expression (82) is the radian. In addition,Phase_a[0], Phase_a[1], Phase_a[2], Phase_a[3], . . . , Phase_a[Na-2],and Phase_a[Na-1] are used to allow the period of the phase change valueYp(i) to be Na. To obtain the period Na, Phase_a[0], Phase_a[1],Phase_a[2], Phase_a[3], . . . , Phase_a[Na-2], and Phase_a[Na-1] may bearranged in any manner. To obtain the period Na, the following holds,for example.

Yp(i=u+v×Na)=Yp(i=u+(v+1)×Na)  Expression (83)

Here, u is an integer from 0 to Na-1, and v is an integer equal to orgreater than 0. With all u and v satisfying these conditions, Expression(83) holds.

In addition, weight combining processing and phase change processing maybe respectively performed by the weight combiner 303 and the phasechangers 305A and 305B as in FIGS. 26, 40, 43, 44 , and so forth, or theprocessing by the weight combiner 303 and the processing by the phasechangers 305A and 305B may be performed by the second signal processor6300 as in FIG. 103 . In FIG. 103 , the elements that operate similarlyto those in FIGS. 26, 40, 43, and 44 are denoted by the same numerals.

For example, in Expression (42), when the matrix for weight combining isrepresented by Fp and the matrix related to phase change is representedby Pp, a matrix Wp(=Pp×Fp) is prepared in advance. In addition, thesecond signal processor 6300 in FIG. 103 may generate the signals 306Aand 306B by using the matrix Wp, the signal 301A (sp1(t)), and thesignal 301B (sp2(t)).

The phase changers 309A, 309B, 3801A, and 3801B in FIGS. 26, 40, 43, and44 may or may not perform signal processing for phase change.

In addition, Na and Nb may be identical values or different values.

As a result of setting the phase change value yp(i) and the phase changevalue Yp(i) in the foregoing manner, it is possible to obtain an effectof an increased possibility that the reception apparatus is able toobtain favorable reception quality due to the spatial diversity effectin an environment in which direct waves are dominant or an environmentin which a multipath or the like exists. Furthermore, as a result oflimiting the number of values that can be taken as the phase changevalue yp(i) and the phase change value Yp(i) as described above, thepossibility of decreasing the circuit scales of the transmissionapparatus and the reception apparatus is increased with the influence onthe data reception quality being decreased.

The present embodiment is highly likely to be effective when beingapplied to the phase change method described in another embodiment inthis specification. However, even when being applied to another phasechange method, the present embodiment can be carried out similarly.

Obviously, the present embodiment and the sixteenth embodiment may becarried out in combination with each other. That is, M phase changevalues may be extracted from Expression (78). Also, Mb phase changevalues may be extracted from Expression (80), or Ma phase change valuesmay be extracted from Expression (82).

Twenty-eighth Embodiment

In the present embodiment, a description will be given of a phase changemethod in a case where the weight combiner 303 and the phase changer305B exist, as in FIGS. 3, 4, 41, 45, 47 , and so forth.

For example, as described in the embodiments, it is assumed that thephase change value in the phase changer 305B is given as yp(i). Here, iis a symbol number, and i is an integer equal to or greater than 0, forexample.

For example, it is assumed that the phase change value yp(i) is theperiod of N. Here, N is an integer equal to or greater than 2. Phase[0],Phase[1], Phase[2], Phase[3], . . . , Phase[N-2], and Phase[N-1] areprepared as the N values. That is, Phase[k] is prepared, where k is aninteger from 0 to N-1. Also, Phase[k] is a real number from 0 radians to2π radians. In addition, u is an integer from 0 to N-1, v is an integerfrom 0 to N-1, and u≠v holds. In all u and v satisfying theseconditions, Phase[u]≠Phase[v] holds. At this time, Phase[k] is expressedby the following expression. Here, k is an integer from 0 to N-1.

$\begin{matrix}{{{Phase}\lbrack k\rbrack} = \frac{k \times 2 \times \pi}{N}} & {{Expression}(84)}\end{matrix}$

Note that the unit of Expression (84) is the radian. In addition,Phase[0], Phase[1], Phase[2], Phase[3], . . . , Phase[N-2], andPhase[N-1] are used to allow the period of the phase change value yp(i)to be N. To obtain the period N, Phase[0], Phase[1], Phase[2], Phase[3],. . . , Phase[N-2], and Phase[N-1] may be arranged in any manner. Toobtain the period N, the following holds, for example.

yp(i=u+v×N)=yp(i=u+(v+1)×N)  Expression (85)

Here, u is an integer from 0 to N-1, and v is an integer equal to orgreater than 0. With all u and v satisfying these conditions, Expression(85) holds.

In addition, weight combining processing and phase change processing maybe respectively performed by the weight combiner 303 and the phasechanger 305B as in FIG. 3 and so forth, or the processing by the weightcombiner 303 and the processing by the phase changer 305B may beperformed by the first signal processor 6200 as in FIG. 102 . In FIG.102 , the elements that operate similarly to those in FIG. 3 are denotedby the same numerals.

For example, in Expression (3), when the matrix for weight combining isrepresented by Fp and the matrix related to phase change is representedby Pp, a matrix Wp(=Pp×Fp) is prepared in advance. In addition, thefirst signal processor 6200 in FIG. 102 may generate the signals 304Aand 306B by using the matrix Wp, the signal 301A (sp1(t)), and thesignal 301B (sp2(t)).

The phase changers 309A, 309B, 3801A, and 3801B in FIGS. 3, 4, 41, 45,and 47 may or may not perform signal processing for phase change.

As a result of setting the phase change value yp(i) in the foregoingmanner, the values that can be taken as the phase change value yp(i)exist evenly on the complex plane from the viewpoint of the phase, andthus the spatial diversity effect can be obtained. Accordingly, it ispossible to obtain an effect of an increased possibility that thereception apparatus is able to obtain favorable reception quality in anenvironment in which direct waves are dominant or an environment inwhich a multipath or the like exists.

Next, a description will be given of a phase change method in a casewhere the weight combiner 303, the phase changer 305A, and the phasechanger 305B exist, as in FIGS. 26, 40, 43, 44 , and so forth.

As described in another embodiment, it is assumed that the phase changevalue in the phase changer 305B is given as yp(i). Here, i is a symbolnumber, and i is an integer equal to or greater than 0, for example.

For example, it is assumed that the phase change value yp(i) is theperiod of Nb. Here, Nb is an integer equal to or greater than 2.Phase_b[0], Phase_b[1], Phase_b[2], Phase_b[3], . . . , Phase_b[Nb-2],and Phase_b[Nb-1] are prepared as the Nb values. That is, Phase_b[k] isprepared, where k is an integer from 0 to Nb-1. Also, Phase_b[k] is areal number from 0 radians to 2π radians. In addition, u is an integerfrom 0 to Nb-1, v is an integer from 0 to Nb-1, and u≠v holds. In all uand v satisfying these conditions, Phase_b[u]≠Phase_b[v] holds. At thistime, Phase_b[k] is expressed by the following expression. Here, k is aninteger from 0 to Nb-1.

$\begin{matrix}{{{Phase\_ b}\lbrack k\rbrack} = \frac{k \times 2 \times \pi}{Nb}} & {{Expression}(86)}\end{matrix}$

Note that the unit of Expression (86) is the radian. In addition,Phase_b[0], Phase_b[1], Phase_b[2], Phase_b[3], . . . , Phase_b[Nb-2],and Phase_b[Nb-1] are used to allow the period of the phase change valueyp(i) to be Nb. To obtain the period Nb, Phase_b[0], Phase_b[1],Phase_b[2], Phase_b[3], . . . , Phase_b[Nb-2], and Phase_b[Nb-1] may bearranged in any manner. To obtain the period Nb, the following holds,for example.

yp(i=u+v×Nb)=yp(i=u+(v+1)×Nb)  Expression (87)

Here, u is an integer from 0 to Nb-1, and v is an integer equal to orgreater than 0. With all u and v satisfying these conditions, Expression(87) holds.

As described in another embodiment, it is assumed that the phase changevalue in the phase changer 305A is given as Yp(i). Here, i is a symbolnumber, and i is an integer equal to or greater than 0, for example. Forexample, it is assumed that the phase change value Yp(i) is the periodof Na. Here, Na is an integer equal to or greater than 2. Phase_a[0],Phase_a[1], Phase_a[2], Phase_a[3], . . . , Phase_a[Na-2], andPhase_a[Na-1] are prepared as the Na values. That is, Phase_a[k] isprepared, where k is an integer from 0 to Na-1. Also, Phase_a[k] is areal number from 0 radians to 2π radians. In addition, u is an integerfrom 0 to Na-1, v is an integer from 0 to Na-1, and u≠v holds. In all uand v satisfying these conditions, Phase_a[u]≠Phase_a[v] holds. At thistime, Phase_a[k] is expressed by the following expression. Here, k is aninteger from 0 to Na-1.

$\begin{matrix}{{{Phase\_ a}\lbrack k\rbrack} = \frac{k \times 2 \times \pi}{Na}} & {{Expression}(88)}\end{matrix}$

Note that the unit of Expression (88) is the radian. In addition,Phase_a[0], Phase_a[1], Phase_a[2], Phase_a[3], . . . , Phase_a[Na-2],and Phase_a[Na-1] are used to allow the period of the phase change valuew(i) to be Na. To obtain the period Na, Phase_a[0], Phase_a[1],Phase_a[2], Phase_a[3], . . . , Phase_a[Na-2], and Phase_a[Na-1] may bearranged in any manner. To obtain the period Na, the following holds,for example.

Yp(i=u+v×Na)=Yp(i=u+(v+1)×Na)  Expression (89)

Here, u is an integer from 0 to Na-1, and v is an integer equal to orgreater than 0. With all u and v satisfying these conditions, Expression(89) holds.

In addition, weight combining processing and phase change processing maybe respectively performed by the weight combiner 303 and the phasechangers 305A and 305B as in FIGS. 26, 40, 43, 44 , and so forth, or theprocessing by the weight combiner 303 and the processing by the phasechangers 305A and 305B may be performed by the second signal processor6300 as in FIG. 103 . In FIG. 103 , the elements that operate similarlyto those in FIGS. 26, 40, 43, and 44 are denoted by the same numerals.

For example, in Expression (42), when the matrix for weight combining isrepresented by Fp and the matrix related to phase change is representedby Pp, a matrix Wp (=Pp×Fp) is prepared in advance. In addition, thesecond signal processor 6300 in FIG. 103 may generate the signals 306Aand 306B by using the matrix Wp, the signal 301A (sp1(t)), and thesignal 301B (sp2(t)).

The phase changers 309A, 309B, 3801A, and 3801B in FIGS. 26, 40, 43, and44 may or may not perform signal processing for phase change.

In addition, Na and Nb may be identical values or different values.

As a result of setting the phase change value yp(i) and the phase changevalue Yp(i) in the foregoing manner, the values that can be taken as thephase change value yp(i) and the phase change value Yp(i) exist evenlyon the complex plane from the viewpoint of the phase, and thus thespatial diversity effect can be obtained. Accordingly, it is possible toobtain an effect of an increased possibility that the receptionapparatus is able to obtain favorable reception quality in anenvironment in which direct waves are dominant or an environment inwhich a multipath or the like exists.

The present embodiment is highly likely to be effective when beingapplied to the phase change method described in another embodiment inthis specification. However, even when being applied to another phasechange method, the present embodiment can be carried out similarly.

Obviously, the present embodiment and the sixteenth embodiment may becarried out in combination with each other. That is, M phase changevalues may be extracted from Expression (84). Also, Mb phase changevalues may be extracted from Expression (86), or Ma phase change valuesmay be extracted from Expression (88).

Sixth Supplement

Regarding the modulation scheme, even if a modulation scheme other thanthe modulation schemes described in this specification is used, theembodiments and the like described in this specification can be carriedout. For example, non-uniform (NU)-QAM, π/2 shift BPSK, π/4 shift QPSK,a PSK scheme in which the phase of a certain value is shifted, or thelike may be used.

The phase changers 309A and 309B may perform Cyclic Delay Diversity(CDD) or Cyclic Shift Diversity (CSD).

In this specification, a description has been given of the mapped signalsp1(t) and the mapped signal sp2(t) that transmit pieces of datadifferent from each other in FIGS. 3, 4, 26, 33, 38, 39, 40, 41, 42, 43,44, 45, 46, 47, 48, 76, 77 , and so forth, for example, but anembodiment is not limited thereto. That is, the mapped signal sp1(t) andthe mapped signal sp2(t) may transmit pieces of data identical to eachother. For example, when the symbol number i=a (a is an integer equal toor greater than 0, for example), the mapped signal sp1(i=a) and themapped signal sp2(i=a) may transmit pieces of data identical to eachother.

The method in which the mapped signal sp1(i=a) and the mapped signalsp2(i=a) transmit pieces of data identical to each other is not limitedto the foregoing method. For example, the mapped signal sp1(i=a) and themapped signal sp2(i=b) may transmit pieces of data identical to eachother (b is an integer equal to or greater than 0, and a≠b).Furthermore, a first data sequence may be transmitted by using multiplesymbols of sp1(i), and a second data sequence may be transmitted byusing multiple symbols of sp2(i).

Twenty-ninth Embodiment

In this specification, in the “user #p signal processor” 102_p includedin the base station in FIGS. 1, 52 , and so forth, the weight combiner(for example, 303) in FIGS. 3, 4, 26, 38, 39, 40, 41, 42, 43, 44, 45,46, 47, 48, 76, 77 , and so forth may include multiple precodingmatrices that can be switched, that is, multiple codebooks. On the basisof feedback information transmitted by the user #p, that is, theterminal #p, the base station may select a precoding matrix forgenerating a modulated signal to be transmitted to the user #p fromamong the switchable precoding matrices, that is, from among switchablecodebooks, and the “user #p signal processor” 102_p may performcomputation of the precoding matrix. The selection of the precodingmatrix or codebook in the base station may be decided by the basestation. Hereinafter, this point will be described.

FIG. 104 illustrates the relationship between the base station and theuser #p, that is, the terminal #p. A base station 6400 transmits amodulated signal (i.e., 6410_p), and the terminal #p denoted by 6401_preceives the modulated signal transmitted by the base station.

For example, it is assumed that the modulated signal transmitted by thebase station 6400 includes reference symbols, a reference signal, apreamble, and the like for estimating the channel state, such as thereception electric field strength.

The terminal #p 6401_p estimates the channel state on the basis of thereference symbols, reference signal, preamble, and the like transmittedby the base station. Subsequently, the terminal #p 6401_p transmits amodulated signal including information about the channel state to thebase station (6411_p). Additionally, in accordance with the channelstate, the terminal #p 6401_p may transmit an indicator of a precodingmatrix that is used by the base station to generate a modulated signalto be transmitted to the terminal #p.

On the basis of the feedback information obtained from the terminal, thebase station 6400 selects a precoding matrix, that is, a codebook, to beused for generating a modulated signal to be transmitted to the terminal#p. A specific example of this operation will be described below.

It is assumed that the weight combiner of the base station is able tocompute “matrix A, matrix B, matrix C, and matrix D” as precodingmatrices, that is, codebooks, which are usable to generate a modulatedsignal to be transmitted to the user #p, that is, the terminal #p. In acase where the base station decides to use “matrix A” as weightcombining to generate a modulated signal to be transmitted to the user#p, that is, the terminal #p, the base station performs weightcombining, that is, precoding, by using “matrix A” in the weightcombiner (for example, 303) in FIGS. 3, 4, 26, 38, 39, 40, 41, 42, 43,44, 45, 46, 47, 48, 76, 77 , and so forth included in the base station,and the base station generates a modulated signal for the user #p, thatis, the terminal #p. Subsequently, the base station transmits thegenerated modulated signal.

Likewise, in a case where the base station decides to use “matrix B” asweight combining to generate a modulated signal to be transmitted to theuser #p, that is, the terminal #p, the base station performs weightcombining, that is, precoding, by using “matrix B” in the weightcombiner (for example, 303) in FIGS. 3, 4, 26, 38, 39, 40, 41, 42, 43,44, 45, 46, 47, 48, 76, 77 , and so forth included in the base station,and the base station generates a modulated signal for the user #p, thatis, the terminal #p. Subsequently, the base station transmits thegenerated modulated signal.

In a case where the base station decides to use “matrix C” as weightcombining to generate a modulated signal to be transmitted to the user#p, that is, the terminal #p, the base station performs weightcombining, that is, precoding, by using “matrix C” in the weightcombiner (for example, 303) in FIGS. 3, 4, 26, 38, 39, 40, 41, 42, 43,44, 45, 46, 47, 48, 76, 77 , and so forth included in the base station,and the base station generates a modulated signal for the user #p, thatis, the terminal #p. Subsequently, the base station transmits thegenerated modulated signal.

In a case where the base station decides to use “matrix D” as weightcombining to generate a modulated signal to be transmitted to the user#p, that is, the terminal #p, the base station performs weightcombining, that is, precoding, by using “matrix D” in the weightcombiner (for example, 303) in FIGS. 3, 4, 26, 38, 39, 40, 41, 42, 43,44, 45, 46, 47, 48, 76, 77 , and so forth included in the base station,and the base station generates a modulated signal for the user #p, thatis, the terminal #p. Subsequently, the base station transmits thegenerated modulated signal.

In the above-described example, four types of matrices are included asprecoding matrices, that is, codebooks, usable by the base station togenerate a modulated signal. However, the number of matrices that areincluded is not limited four, and the embodiment can be carried outsimilarly as long as multiple matrices are included. In addition, thephase change described in this specification may or may not be performedafter the weight combining. At this time, whether or not to perform thephase change may be switched by a control signal or the like.

Likewise, also in the multiplexing signal processor 104 in FIG. 1 ,multiple matrices (also be called codebooks) to be used to generate anoutput signal (modulated signal) may be prepared, and the base stationmay select a matrix to be used in the multiplexing signal processor 104in FIG. 1 on the basis of the feedback information from the terminal,and may generate an output signal by using the selected matrix. Theselection of the matrix to be used may be decided by the base station.Hereinafter, this point will be described. The communication between thebase station and the terminal has been described above by using FIG. 104, and thus the description is omitted.

It is assumed that the multiplexing signal processor 104 of the basestation is able to compute “matrix α, matrix β, matrix γ, and matrix δ”as matrices, that is, codebooks, which are usable to generate amodulated signal to be transmitted to the terminal. In a case where thebase station decides to use “matrix α” as processing in the multiplexingsignal processor, the base station performs multiplexing signalprocessing by using “matrix α” in the multiplexing signal processor inFIG. 1 and so forth included in the base station to generate a modulatedsignal, and the base station transmits the generated modulated signal.

Likewise, in a case where the base station decides to use “matrix β” asprocessing in the multiplexing signal processor, the base stationperforms multiplexing signal processing by using “matrix β” in themultiplexing signal processor in FIG. 1 and so forth included in thebase station to generate a modulated signal, and the base stationtransmits the generated modulated signal.

In a case where the base station decides to use “matrix γ” as processingin the multiplexing signal processor, the base station performsmultiplexing signal processing by using “matrix γ” in the multiplexingsignal processor in FIG. 1 and so forth included in the base station togenerate a modulated signal, and the base station transmits thegenerated modulated signal.

In a case where the base station decides to use “matrix δ” as processingin the multiplexing signal processor, the base station performsmultiplexing signal processing by using “matrix δ” in the multiplexingsignal processor in FIG. 1 and so forth included in the base station togenerate a modulated signal, and the base station transmits thegenerated modulated signal.

In the above-described example, four types of matrices are included asmatrices, that is, codebooks, usable by the base station to generate amodulated signal. However, the number of matrices that are included isnot limited four, and the embodiment can be carried out similarly aslong as multiple matrices are included.

It is assumed that the multiplexing signal processor 7000_p in FIG. 70of the base station is able to compute “matrix P, matrix Q, matrix R,and matrix S” as precoding matrices, that is, codebooks, which areusable to generate a modulated signal to be transmitted to the user #p,that is, the terminal #p. Here, p is an integer from 1 to M. In a casewhere the base station decides to use “matrix P” as multiplexing signalprocessing to generate a modulated signal to be transmitted to the user#p, that is, the terminal #p, the base station performs multiplexingsignal processing by using “matrix P” in the multiplexing signalprocessor 7000_p in FIG. 70 included in the base station to generate amodulated signal for the user #p, that is, the terminal #p.Subsequently, the base station transmits the generated modulated signal.

Likewise, in a case where the base station decides to use “matrix Q” asmultiplexing signal processing to generate a modulated signal to betransmitted to the user #p, that is, the terminal #p, the base stationperforms multiplexing signal processing by using “matrix “Q” in themultiplexing signal processor 7000_p in FIG. 70 included in the basestation to generate a modulated signal for the user #p, that is, theterminal #p. Subsequently, the base station transmits the generatedmodulated signal.

In a case where the base station decides to use “matrix R” asmultiplexing signal processing to generate a modulated signal to betransmitted to the user #p, that is, the terminal #p, the base stationperforms multiplexing signal processing by using “matrix “R” in themultiplexing signal processor 7000_p in FIG. 70 included in the basestation to generate a modulated signal for the user #p, that is, theterminal #p. Subsequently, the base station transmits the generatedmodulated signal.

In a case where the base station decides to use “matrix S” asmultiplexing signal processing to generate a modulated signal to betransmitted to the user #p, that is, the terminal #p, the base stationperforms multiplexing signal processing by using “matrix “S” in themultiplexing signal processor 7000_p in FIG. 70 included in the basestation to generate a modulated signal for the user #p, that is, theterminal #p. Subsequently, the base station transmits the generatedmodulated signal.

In the above-described example, four types of matrices are included asprecoding matrices, that is, codebooks, usable by the base station togenerate a modulated signal. However, the number of matrices that areincluded is not limited four, and the embodiment can be carried outsimilarly as long as multiple matrices are included.

When the individual elements operate in the manner described above inthe present embodiment, the effects described in this specification canbe obtained similarly. Thus, the present embodiment can be carried outin combination with another embodiment described in this specification,and the effects described in each embodiment can be obtained similarly.

Thirtieth Embodiment

In the description of the first embodiment to the twenty-ninthembodiment, a description has been given of the cases of theconfigurations in FIGS. 1, 70 , and so forth as the configuration of thebase station or AP. That is, a description has been given of a casewhere the base station is able to simultaneously transmit modulatedsignals to multiple users, that is, multiple terminals. In the presentembodiment, a description will be given of an example of a case wherethe base station or AP has the configuration in FIG. 105 .

FIG. 105 illustrates the configuration of the base station or AP in thepresent embodiment.

An error-correcting encoder 6502 receives data 6501 and a control signal6500, performs error-correcting coding on the data 6501 on the basis ofinformation about an error-correcting code included in the controlsignal 6500, for example, information about an error-correcting codingscheme, a coding rate, or the like, and outputs error-correcting codeddata 6503.

A mapper 6504 receives the control signal 6500 and the error-correctingcoded data 6503, performs mapping on the basis of information about amodulation scheme included in the control signal 6500, and outputs astream #1 baseband signal 6505_1 and a stream #2 baseband signal 6505_2.

A signal processor 6506 receives the control signal 6500, the stream #1baseband signal 6505_1, the stream #2 baseband signal 6505_2, and asignal group 110, performs signal processing on the stream #1 basebandsignal 6505_1 and the stream #2 baseband signal 6505_2 on the basis ofinformation about a transmission method included in the control signal6500, and generates and outputs a first modulated signal 6506_A and asecond modulated signal 6506_B.

A radio section 6507_A receives the first modulated signal 6506_A andthe control signal 6500, performs processing such as frequencyconversion on the first modulated signal 6506_A, and outputs a firsttransmission signal 6508_A. The first transmission signal 6508_A isoutputs as a radio wave from an antenna section #A 6509_A.

Likewise, a radio section 6507_B receives the second modulated signal6506_B and the control signal 6500, performs processing such asfrequency conversion on the second modulated signal 6506_B, and outputsa second transmission signal 6508_B. The second transmission signal6508_B is outputs as a radio wave from an antenna section #B 6509_B.

The first transmission signal 6508_A and the second transmission signal6508_B are signals at identical times and identical frequencies (bands).

The signal processor 6506 in FIG. 105 has the configuration in any ofFIGS. 3, 4, 26, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 76, and 77 ,for example. At this time, the signal 6505_1 in FIG. 105 corresponds tothe signal 301A, the signal 6505_2 corresponds to the signal 301B, andthe signal 6500 corresponds to the signal 300. There are output signalsof two systems in FIGS. 3, 4, 26, 38, 39, 40, 41, 42, 43, 44, 45, 46,47, 48, 76, and 77 . The output signals of two systems correspond to thesignals 6506_A and 6506_B in FIG. 105 .

The signal processor 6506 in FIG. 105 has any one of the configurationsin FIGS. 3, 4, 26, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 76, and77 , for example. That is, it may be considered as a transmissionapparatus supporting a single user Multiple Input Multiple Output(MIMO).

Thus, in the case of carrying out each of the first embodiment to thetwenty-ninth embodiment, the base station transmits modulated signals tomultiple terminals in a certain time band and a certain frequency band,as illustrated in FIG. 24 , but the base station including thetransmission apparatus in FIG. 105 transmits a modulated signal to asingle terminal in a certain time band and a certain frequency band.Thus, the base station including the transmission apparatus in FIG. 105communicates with the terminal #p=1 in each of the first embodiment tothe twenty-ninth embodiment, and carries out each of the firstembodiment to the twenty-ninth embodiment. In this way, each of thefirst embodiment to the twenty-ninth embodiment can be carried out, andthe effects described in each embodiment can be obtained similarly.

The base station including the transmission apparatus in FIG. 105 isable to communicate with multiple terminals by using Time DivisionMultiple Access (TDMA) and/or Frequency Division Multiple Access (FDMA)and/or Code Division Multiple Access (CDMA).

Obviously, the embodiments and the like described in this specificationmay be carried out in combination with one another.

Each embodiment is merely an example. For example, even if a “modulationscheme, error-correcting coding scheme (error-correcting code, codelength, and coding rate to be used), control information, and so forth”are given as examples, the embodiment can be carried out with a similarconfiguration by applying another “modulation scheme, error-correctingcoding scheme (error-correcting code, code length, and coding rate to beused), control information, and so forth”.

Regarding the modulation scheme, even if a modulation scheme other thanthe modulation schemes described in this specification is used, theembodiments and the like described in this specification can be carriedout. For example, Amplitude Phase Shift Keying (APSK) (for example,16APSK, 64APSK, 128APSK, 256APSK, 1024APSK, 4096APSK, and the like),Pulse Amplitude Modulation (PAM) (for example, 4PAM, 8PAM, 16PAM, 64PAM,128PAM, 256PAM, 1024PAM, 4096PAM, and the like), Phase Shift Keying(PSK) (for example, BPSK, QPSK, 8PSK, 16PSK, 64PSK, 128PSK, 256PSK,1024PSK, 4096PSK, and the like), Quadrature Amplitude Modulation (QAM)(for example, 4QAM, 8QAM, 16QAM, 64QAM, 128QAM, 256QAM, 1024QAM,4096QAM, and the like), and the like may be used, and uniform mapping ornon-uniform mapping may be used in each modulation scheme. In addition,the method for arranging 2, 4, 8, 16, 64, 128, 256, and 1024 signalpoints on the I-Q plane (the modulation scheme having 2, 4, 8, 16, 64,128, 256, and 1024 signal points) is not limited to the signal pointarrangement method in the modulation schemes described in thisspecification.

In this specification, the transmission apparatus may be included in,for example, a communication/broadcasting apparatus such as a broadcaststation, a base station, an access point, a terminal, or a mobile phone.At this time, the reception apparatus may be included in a communicationapparatus such as a television receiver, a radio, a terminal, a personalcomputer, a mobile phone, an access point, or a base station. Inaddition, the transmission apparatus and the reception apparatus in thepresent disclosure are apparatuses having a communication function.These apparatuses may be connectable to an apparatus for executing anapplication, such as a television receiver, a radio, a personalcomputer, or a mobile phone, through a certain interface. In addition,in the present embodiment, symbols other than data symbols, for example,pilot symbols (preamble, unique word, postamble, reference symbols, orthe like), control information symbols, and so forth may be arranged ina frame in any manner. Here, the terms “pilot symbols” and “controlinformation symbols” are used, but other terms may also be used, and thefunctions thereof are important.

For example, the pilot symbols may be known symbols modulated by usingPSK modulation in a transmitter/receiver (or the receiver may be able tolearn symbols transmitted by the transmitter by synchronization). Thereceiver performs frequency synchronization, time synchronization,channel estimation (estimation of channel state information (CSI) foreach modulated signal, signal detection, and so forth by using thesesymbols.

The control information symbols are symbols for transmitting informationthat needs to be transmitted to a communication partner for realizingcommunication other than data (of an application or the like) (forexample, the modulation scheme, the error-correcting coding scheme, andthe coding rate of the error-correcting coding scheme used incommunication, setting information in an upper layer, and so forth).

The present disclosure is not limited to the individual embodiments, andvarious modifications may be carried out. For example, each embodimentdescribes a case where the present disclosure is applied to acommunication apparatus, but the present disclosure is not limitedthereto. The communication method can be implemented as software.

For example, a program that executes the above-described communicationmethod may be store in a read only memory (ROM) in advance, and theprogram may be executed by a central processing unit (CPU).

In addition, a program that executes the above-described communicationmethod may be stored in a computer-readable storage medium, the programstored in the storage medium may be recorded in a random access memory(RAM) of a computer, and the computer may be allowed to operate inaccordance with the program.

The individual elements of each of the above-described embodiments maytypically be implemented as large scale integration (LSI) serving as anintegrated circuit. These elements may be individually formed on chips,or all or some of the elements of each embodiment may be formed on asingle chip. Although LSI is used here, the terms such as an integratedcircuit (IC), system LSI, super LSI, or ultra LSI may be used inaccordance with the degree of integration. The method for circuitintegration is not limited to LSI, and may be realized by using adedicated circuit or general-purpose processor. A field programmablegate array (FPGA) that can be programmed after LSI manufacturing, or areconfigurable processor in which the connections and settings of acircuit cell in LSI are reconfigurable may be used. Furthermore, if theprogress of semiconductor technologies or other derived technologiesproduce a circuit integration technology that replaces LSI, integrationof functional blocks may of course be performed by using the technology.Application of biotechnology or the like is possible.

In this specification, various frame configurations have been described.It is assumed that a modulated signal having a frame configurationdescribed in this specification is transmitted by, for example, a basestation (AP) including the transmission apparatus in FIG. 1 by using amulti-carrier scheme such as the OFDM scheme. At this time, anapplication method can be considered in which, when the terminal (user)communicating with the base station (AP) transmits a modulated signal,the modulated signal transmitted by the terminal is based on asingle-carrier scheme (the base station (AP) is able to simultaneouslytransmit a data symbol group to multiple terminals by using the OFDMscheme, and the terminal is able to reduce power consumption by usingthe single-carrier scheme).

The embodiment using the single-carrier scheme is also applicable to themulti-carrier scheme. Furthermore, if the method described as a methodfor increasing the reception quality in an environment in which directwaves are dominant is applied to another channel mode, there is apossibility that the reception quality increases. Thus, the presentdisclosure can generally be applied to wireless communication.

In addition, by using a part of the frequency band used by a modulatedsignal transmitted by the base station (AP), the terminal may apply aTime Division Duplex (TDD) scheme for transmitting a modulated signal.

The present disclosure is useful to a communication apparatus, such as abase station.

What is claimed is:
 1. A transmission apparatus comprising: a modulationmapper, which, in operation, when a phase change before precoding isenabled, modulates a bit sequence to generate a symbol sequence to whicha first phase change before precoding is applied, an amount of the firstphase change before precoding being cyclically switched; and when aphase change before precoding is not enabled, modulates a bit sequenceto generate a symbol sequence to which the first phase change beforeprecoding is not applied; and a precoder, which, in operation, when themodulation mapper outputs the symbol sequence to which the first phasechange before precoding is applied, performs precoding on the symbolsequence to generate a first precoded signal and a second precodedsignal, wherein a second phase change is applied to the second precodedsignal; and when the modulation mapper outputs the symbol sequence towhich the first phase change before precoding is not applied, performsprecoding on the symbol sequence to generate a third precoded signal anda fourth precoded signal.
 2. The transmission apparatus according toclaim 1, wherein a third phase change and a fourth phase change areapplied to the third precoded signal and the fourth precoded signal,respectively, and an amount of the third phase change and an amount ofthe fourth phase change are selected from a plurality of commoncandidate amounts.
 3. The transmission apparatus according to claim 1,comprising a transmitter, which, in operation, transmits the firstprecoded signal and the second precoded signal or transmits the thirdprecoded signal and the fourth precoded signal, wherein the transmitteruses at least one of a first orthogonal frequency-division multiplexing(OFDM) transmission mode or another transmission mode different from thefirst OFDM transmission mode.
 4. The transmission apparatus according toclaim 1, wherein when a phase change before precoding is enabled, π/2shift Binary Phase Shift Keying (BPSK) is used at the modulation mapperand the amount of the first phase change before precoding is switchedsymbol by symbol.
 5. The transmission apparatus according to claim 1,wherein the second phase change is not applied to the first precodedsignal.
 6. The transmission apparatus according to claim 1, wherein anamount of the second phase change is selected from a plurality ofcandidate amounts and the selected amount is used as a fixed value for aperiod.
 7. The transmission apparatus according to claim 1, wherein eachof the third precoded signal and the fourth precoded signal is anorthogonal frequency-division multiplexing (OFDM) symbol sequence. 8.The transmission apparatus according to claim 1, comprising atransmitter including a plurality of antenna ports, wherein each of theplurality of antenna ports transmits at least one of the first precodedsignal or the second precoded signal, or at least one of the thirdprecoded signal or the fourth precoded signal.
 9. A transmission methodcomprising: when a phase change before precoding is enabled, modulatinga bit sequence to generate a symbol sequence to which a first phasechange before precoding is applied, an amount of the first phase changebefore precoding being cyclically switched; performing precoding on thesymbol sequence to generate a first precoded signal and a secondprecoded signal, wherein a second phase change is applied to the secondprecoded signal; and when a phase change before precoding is notenabled, modulating a bit sequence to generate a symbol sequence towhich the first phase change before precoding is not applied; andperforming precoding on the symbol sequence to generate a third precodedsignal and a fourth precoded signal.
 10. The transmission methodaccording to claim 9, wherein a third phase change and a fourth phasechange are applied to the third precoded signal and the fourth precodedsignal, respectively, and an amount of the third phase change and anamount of the fourth phase change are selected from a plurality ofcommon candidate amounts.
 11. The transmission method according to claim9, comprising transmitting the first precoded signal and the secondprecoded signal or transmitting the third precoded signal and the fourthprecoded signal, wherein the transmitting uses at least one of a firstorthogonal frequency-division multiplexing (OFDM) transmission mode oranother transmission mode different from the first OFDM transmissionmode.
 12. The transmission method according to claim 9, wherein when aphase change before precoding is enabled, π/2 shift Binary Phase ShiftKeying (BPSK) is used at the modulating of the bit sequence and theamount of the first phase change before precoding is switched symbol bysymbol.
 13. The transmission method according to claim 9, wherein thesecond phase change is not applied to the first precoded signal.
 14. Thetransmission method according to claim 9, wherein an amount of thesecond phase change is selected from a plurality of candidate amountsand the selected amount is used as a fixed value for a period.
 15. Thetransmission method according to claim 9, wherein each of the thirdprecoded signal and the fourth precoded signal is an orthogonalfrequency-division multiplexing (OFDM) symbol sequence.
 16. Thetransmission method according to claim 9, wherein the transmitting isperformed by using a plurality of antenna ports, and each of theplurality of antenna ports transmits at least one of the first precodedsignal or the second precoded signal, or at least one of the thirdprecoded signal or the fourth precoded signal.